MAGNESIUM SULFATE-D5W

Magnesium is the second most abundant intracellular cation. It is has been identified as a cofactor in more than 300 enzymatic reactions involving energy metabolism and protein and nucleic acid synthesis. Several magnesium salts are used clinically. Magnesium chloride, magnesium gluconate, magnesium lactate, and magnesium oxide are oral products used for supplementation in patients with magnesium deficiency due to malnutrition, restricted diet, or magnesium-depleting drugs. Magnesium oxide may also be used as an antacid or laxative.

Magnesium sulfate is the most commonly used of the magnesium salts and can be administered orally or parenterally. It is used orally as a laxative and parenterally as a neuromuscular depressant or to treat hypomagnesemia. Oral magnesium sulfate belongs to the class of saline laxatives, which are used primarily to empty the bowel before surgery or radiologic, proctoscopic, or sigmoidoscopic procedures. Magnesium sulfate is also a useful cathartic in combination with charcoal to treat acute drug overdose because charcoal will not bind inorganic compounds like magnesium sulfate. The primary use of parenteral magnesium sulfate is to prevent and control seizures in preeclampsia and eclampsia. Parenteral magnesium sulfate is also useful in controlling seizures due to epilepsy, glomerulonephritis, or hypothyroidism. Parenteral magnesium may also be considered in the treatment of cardiac glycoside-induced arrhythmias. Routine use of magnesium for cardiac arrest is not recommended. Magnesium may be considered for torsades de pointes (i.e., polymorphic ventricular tachycardia associated with a long QT interval).

General Administration Information
For storage information, see the specific product information within the How Supplied section.

Route-Specific Administration

Oral Administration
Oral Solid Formulations
-Oral tablets or capsules: Take magnesium with a full glass of water.
-Magnesium sulfate crystals: Dissolve in a full glass of water prior to administration; lemon-flavored carbonated beverages may be used to mask the bitter taste. Administer on an empty stomach for a more rapid effect. Follow each dose with a full glass of water to prevent dehydration. Do not administer at bedtime or late in the evening.

Oral Liquid Formulations
Powder for Oral Solution (Magnesium Oxide)

-Mix contents of packet with liquid or soft food such as applesauce.
-Mixing with soft food: Pour contents of 1 powder packet on top of soft food in a cup; place another spoonful of soft food on top and mix. Ensure entire contents of cup are consumed. Take soon after mixing.
-Mixing with liquid (e.g., water): Pour contents of 1 powder packet into a medicine cup and add approximately 15 mL of water. Stir to ensure that the powder is completely mixed. Administer immediately after mixing. If the product is not administered immediately, stir again before administering.
-Feeding tube: Products administered via a feeding tube should be prepared separately and administered one at a time. Flush tube with approximately 15 mL of water before and after administering each product.



Injectable Administration
-Magnesium sulfate is administered intramuscularly or intravenously.
-Visually inspect parenteral products for particulate matter and discoloration prior to administration whenever solution and container permit.
Intravenous Administration
-Magnesium sulfate concentration should generally not exceed 200 mg/mL (20%).
-According to the manufacturer, the rate should not exceed 150 mg/minute, except for emergent indications. Rapid infusion rates may exceed the urinary magnesium excretion threshold resulting in hypermagnesemia, which may increase the risk of adverse effects.
-For asymptomatic patients, do not exceed a rate of 1 gram/hour (8 mEq/hour), with a total dose not to exceed 12 grams (approximately 100 mEq) over 12 hours.
-For severe symptomatic hypomagnesemia, up to 4 grams (32 mEq) may be administered over 4 to 5 minutes. Monitor closely for signs of hypermagnesemia.
-For pulseless cardiac arrest associated with torsade de pointes, 1 to 2 grams (diluted in 10 mL 5% Dextrose Injection) may be administered IV over 15 minutes. Previous guidelines recommended that if a pulse was present, 1 to 2 grams diluted in 50 to 100 mL 5% Dextrose Injection, may be infused IV slowly over 5 to 60 minutes. Infuse more slowly in stable patients; rapid infusions can result in adverse effects (e.g. hypotension).
-During intravenous magnesium therapy, an intravenous calcium preparation (e.g., calcium gluconate) should be readily available as a reversal agent in case symptomatic hypermagnesemia occurs.

Intramuscular Administration
-For adults, magnesium sulfate concentrations of 250 mg/mL (25%) or 500 mg/mL (50%) are generally used. For infants and children, concentrations should not exceed 200 mg/mL (20%).
-Inject into a large muscle mass, preferably into a gluteal site.

Other Injectable Administration
Intraosseous infusion
NOTE: Magnesium sulfate is not FDA-approved for intraosseous administration.
-During cardiopulmonary resuscitation, the same dosage may be given via the intraosseous route when IV access is not available.



Inhalation Administration
Oral Inhalation Administration
NOTE: Magnesium sulfate is not FDA-approved for oral inhalation administration.
-Although evidence is limited, studies report administering injectable isotonic magnesium sulfate, sometimes mixed with albuterol or ipratropium, via a nebulizer for the treatment of acute asthma.
-One study reports using isotonic magnesium in the form of a 6.3% solution of magnesium heptahydrate, which is equivalent to 3.18% anhydrous magnesium sulfate.

The most frequently reported adverse reactions of parenteral magnesium sulfate are hypermagnesemia and signs and symptoms of magnesium toxicity. These reactions are characterized by flushing, diaphoresis, hypotension, depressed deep tendon reflexes, muscle paralysis, weakness, hypothermia, circulatory collapse, and cardiac, CNS, or respiratory depression. Deep tendon reflexes may be decreased at serum magnesium concentrations of 4 mEq/L resulting in muscle weakness and hyporeflexia; patellar reflexes usually become hypoactive or disappear at magnesium concentrations more than 8 mEq/L. Respiratory depression or cardiac conduction abnormalities (e.g., AV block) are noted most commonly at serum magnesium concentrations of 10 mEq/L or higher. Magnesium levels more than 12 mEq/L may be fatal due to respiratory arrest, or from cardiac arrest secondary to complete heart block. Magnesium toxicity (conduction abnormalities or respiratory depression) can be reversed by discontinuation of magnesium therapy and the use of intravenous calcium gluconate. Rapid administration (administered faster than 1 g/min) of intravenous magnesium sulfate may result in clinically significant hypotension or asystole and should be avoided. Injection site reaction has been reported following intramuscular injection of magnesium sulfate. Hypocalcemia with signs of tetany has occurred following administration of magnesium sulfate for eclampsia. One case of fetal sinus bradycardia has been reported in the use of magnesium sulfate infusion for pre-term labor; stopping the magnesium infusion resulted in a return to pretreatment basal fetal heart rate. The most common adverse reaction with oral magnesium salts is diarrhea.

Injectable magnesium formulations contain aluminum. Thus, aluminum toxicity may occur with prolonged administration in high-risk patients, including those with renal impairment and premature neonates. Premature neonates are at particular risk for aluminum toxicity because of immature renal function and they require large amounts of calcium and phosphate solutions, which contain aluminum. Research indicates that patients with renal impairment, who receive parenteral aluminum at rates greater than 4-5 mcg/kg/day, may develop aluminum toxicity (CNS and bone toxicity). Tissue loading may occur at lower administration rates.

Parenteral magnesium should be avoided in patients with AV block because it can exacerbate this condition. If parenteral treatment with magnesium salts is necessary, magnesium should be infused at a slower rate and magnesium levels monitored closely. Cardiac disease in the form of myocardial damage generally is considered a contraindication of magnesium salts; however, magnesium sulfate has been used in acute myocardial infarction patients to prevent arrhythmias. Magnesium salts should be used with caution in patients with electrolyte imbalance; do not use magnesium salts in patients with preexisting hypermagnesemia.

Magnesium salts should be used with caution in patients with renal disease, including patients with renal impairment or renal failure. Magnesium salts are renally eliminated, so patients with renal impairment have an increased risk of developing magnesium toxicity from decreased excretion of magnesium. In patients with severe renal dysfunction, no more than 20 grams (162 mEq) of magnesium should be administered within a 48-hour period. Parenteral magnesium should be avoided in patients with a creatinine clearance of less than 20 mL/minute. Up to 30% of an orally administered dose is absorbed systemically.

When used as laxatives, oral magnesium salts should be avoided in patients with GI obstruction or ileus.

Use oral magnesium salts cautiously in dehydrated patients. Repeated administration of oral magnesium salts may lead to severe dehydration due to fluid losses via the gastrointestinal tract.

Parenteral magnesium sulfate is classified as FDA pregnancy risk category D and oral magnesium sulfate and other oral magnesium salts are classified pregnancy category B. Parenteral magnesium chloride is classified as pregnancy risk category C. Parenteral magnesium sulfate readily crosses the placenta and rapidly attains fetal serum concentrations that approximate those in the mother. Serum magnesium concentrations and clinical status must be carefully monitored in the mother during parenteral therapy, especially with high dose use prior to delivery. In addition, all neonates with a history of prolonged in utero exposure to parenteral magnesium sulfate should be monitored carefully for hypocalcemia and bone abnormalities. Continuous administration of magnesium sulfate as a tocolytic during pregnancy beyond 5-7 days has resulted in bone abnormalities, including skeletal demineralization, osteopenia, and neonatal fracture. The shortest duration of therapy that can result in fetal harm is unknown. Eighteen cases of skeletal abnormalities have been identified in neonates exposed in utero to magnesium sulfate in the FDA's Adverse Event Reporting System (AERS). The average duration of in utero exposure to magnesium sulfate was 9.6 weeks (range 8-12 weeks) with an average total maternal dose of 3700 g. Skeletal abnormalities included osteopenia and multiple fractures of the ribs and long bones. In cases with reported outcomes, fractures were transient and resolved. An epidemiologic study also found an association for an increase in bone abnormalities in neonates with in utero exposure to magnesium sulfate for more than 7 days compared with those exposed < 3 days. The long-term effects of altered laboratory tests and/or radiographic findings suggestive of skeletal abnormalities are unknown. One study in 11 babies reported no radiographic bone abnormalities at 1 and 3 years of age in those that had evidence of bone abnormalities at birth. Other adverse neonatal effects after in utero exposure to magnesium sulfate, particularly when given more than 24 hours before delivery, include hypotonia (reduced reflexes), drowsiness/somnolence, and respiratory depression. When used short-term prior to delivery in patients with preeclampsia or eclampsia, the effects of magnesium in the neonate may be similar to those in the mother; however, such effects appear rare with proper use and monitoring.

Magnesium is distributed into breast milk. Intravenous magnesium sulfate therapy only increases magnesium concentrations in human milk slightly, and oral magnesium products should not raise human milk concentrations much at all, particularly if not used for extended periods. Problems with other magnesium salts have not been demonstrated with normal daily recommended amounts during breast-feeding; the concentration of magnesium in breast milk is not influenced by maternal magnesium intake.

Elemental Magnesium Content
One (1) gram of the various magnesium salts contain the following amounts of elemental magnesium:
-magnesium chloride: 120 mg (9.8 mEq) elemental magnesium.
-magnesium gluconate: 54 mg (4.5 mEq) elemental magnesium.
-magnesium lactate: 120 mg (10 mEq) elemental magnesium.
-magnesium oxide: 603 mg (50.3 mEq) elemental magnesium.
-magnesium sulfate: 98 mg (8.12 mEq) elemental magnesium.

For the treatment of hypomagnesemia (see indications for specific associated arrhythmias when present):
NOTE: Serum magnesium concentrations do not accurately predict cellular magnesium stores.
NOTE: The appropriate route of administration for replacement magnesium is dependent on patient symptoms and the severity of hypomagnesemia. Intravenous magnesium replacement should be used initially for patients with clinically severe conditions, and follow-up oral therapy may also be required to fully replenish body stores.
Intravenous dosage (magnesium sulfate):
Adults: 1 to 2 g IV (or 15 to 30 mg/kg lean body weight) every 6 hours for 24 hours. Use the higher end of the dosage range for serum magnesium concentrations less than 1.2 mg/dL. For extreme hypomagnesemia, 8 to 12 g/day IV in divided doses have been used. After the first 24 hours, approximately 60 mg/kg/day may be given in divided doses or as a continuous infusion for the next 2 to 5 days.
Neonates, Infants, Children, and Adolescents: 25 to 50 mg/kg/dose IV over 30 to 60 minutes (Max: 2 g/dose). Repeat as necessary based on serum magnesium concentrations.
Intramuscular dosage:
Adults: 1 to 2 g IM (or 15 to 30 mg/kg lean body weight) every 6 hours for 24 hours is recommended in the FDA-approved labeling; however, IV administration is preferred in clinical practice.
Infants, Children, and Adolescents: 20 to 40 mg/kg/dose IM (Max: 2 g/dose) of a 20% solution is recommended in the FDA-approved labeling; however, IV administration is preferred in clinical practice. Doses may be repeated as necessary based on serum magnesium concentrations. The maximum dose recommended in the FDA-approved labeling for older children is 5 g/day for severe hypomagnesemia and 2 g/day for mild or moderate hypomagnesemia.
Neonates: 20 to 40 mg/kg/dose IM of a 20% solution is recommended in the FDA-approved labeling for pediatric patients; however, IM administration is not commonly utilized in clinical practice. In general, IM administration of drugs in neonates, particularly very low birth weight premature neonates, is not practical due to small muscle mass, and absorption is unreliable due to hemodynamic instability that is relatively common in this population. Doses may be repeated as necessary based on serum magnesium concentrations.
Oral dosage (magnesium chloride, magnesium gluconate, magnesium lactate, magnesium oxide, or magnesium sulfate):
Adults: Dosage is dependent on severity of deficit and individual patient response; 360 to 672 mg elemental magnesium PO daily in divided doses for severe hypomagnesemia or 120 to 336 mg elemental magnesium PO daily in divided doses for mild, asymptomatic hypomagnesemia has been recommended. Another source suggests 20 to 50 mmol (480 to 1200 mg) PO daily in divided doses, depending on route and extent of loss.
Infants, Children, and Adolescents: 10 to 40 mg elemental magnesium/kg/day PO in 2 to 4 divided doses is the general dose range. Higher doses (100 mg elemental magnesium/kg/day PO) have been reported ; however, the use of higher doses may be limited by the occurrence of diarrhea. Titrate dose based on serum magnesium concentrations.
Oral dosage (magnesium sulfate):
Adults: 3 g PO every 6 hours for 4 doses.

For nutritional supplementation:
-the recommended dietary allowance (RDA) of magnesium for nutritional supplementation in healthy individuals:
NOTE: Use dosage based on age for lactating females.
Oral dosage expressed in elemental magnesium:
Adult pregnant females: 350 mg to 360 mg PO per day is the RDA.
Adult females 31 years and older: 320 mg PO per day is the RDA.
Adult females up to 30 years of age: 310 mg PO per day is the RDA.
Adult males 31 years and older: 420 mg PO per day is the RDA.
Adult males up to 30 years of age: 400 mg PO per day is the RDA.
Adolescent pregnant females: 400 mg PO per day is the RDA.
Adolescent females 14 to 18 years of age: 360 mg PO per day is the RDA.
Adolescent males 14 to 18 years of age: 410 mg PO per day is the RDA.
Children 9 to 13 years of age: 240 mg PO per day is the RDA.
Children 4 to 8 years of age: 130 mg PO per day is the RDA.
Children 1 to 3 years of age: 80 mg PO per day is the RDA.
Infants 6 to 12 months of age: 75 mg PO per day based on adequate intake (AI); RDA has not been established.
Neonates and Infants less than 6 months of age: 30 mg PO per day based on adequate intake (AI); RDA has not been established.
-to prevent hypomagnesemia in patients receiving total parenteral nutrition (TPN):
Intravenous dosage as magnesium sulfate:
Adults: 16 to 24 mEq IV per day admixed with TPN, dosage requirements vary with renal function. Undialyzed patients with renal failure generally require 0 to 8 mEq of magnesium sulfate.
Children and Adolescents: Recommendations are based on weight; individualize dosage according to monitoring. For weight 50 kg and less, 0.3 to 0.5 mEq/kg/day IV. For weight greater than 50 kg, 10 to 30 mEq/day IV.
Neonates and Infants: 0.3 to 0.5 mEq/kg/day IV. Individualize dosage according to monitoring.

For the treatment of torsade de pointes* (irregular/polymorphic ventricular tachycardia* associated with QT prolongation) or other cardiac arrhythmias associated with documented hypomagnesemia (e.g., ventricular fibrillation*), including use during cardiopulmonary resuscitation* (cardiac arrest*):
Intravenous or Intraosseous* dosage (magnesium sulfate):
Adults: 1 to 2 g IV or IO. Magnesium may be considered for torsade de pointes. Routine use of magnesium for polymorphic VT with a normal QT interval, ventricular fibrillation, pulseless ventricular tachycardia, or cardiac arrest is not recommended.
Infants, Children, and Adolescents: 25 to 50 mg/kg/dose (Max: 2 g/dose) IV or IO. Administer by rapid bolus (over several minutes) for pulseless torsades de pointes and over 10 to 20 minutes for hypomagnesemia/torsades de pointes with pulse.
Neonates: 25 to 50 mg/kg/dose IV or IO. Administer by rapid bolus (over several minutes) for pulseless torsades de pointes and over 10 to 20 minutes for hypomagnesemia/torsades de pointes with pulse.

For the treatment of cardiac glycoside-induced arrhythmias (e.g., digoxin toxicity*):
Intravenous dosage (magnesium sulfate):
Adults: 1 to 2 g IV diluted in 50 to 100 mL 5% Dextrose and administered over over 15 to 60 minutes (rate dependent on clinical urgency). In clinical trials, higher doses up to 6 g have been administered IV by slow injection over several minutes; however, the risk of hypotension and asystole accompanies rapid IV infusion. Therefore, rapid infusion of high doses of IV magnesium sulfate should be avoided. Correct hypomagnesemia if present. May follow with continuous infusion if needed.
Infants, Children, and Adolescents: 25 to 50 mg/kg/dose (Max: 2 g/dose) IV or via intraosseous (IO) infusion over 15 to 60 minutes. Rapid infusion of high doses of IV magnesium sulfate should be avoided. Correct hypomagnesemia if present.

For the treatment of status asthmaticus*:
Intravenous dosage (magnesium sulfate):
Adults: 2 g IV as a single dose. Intravenous magnesium sulfate decreased admission rates and significantly improved FEV1 at 120 minutes and 240 minutes in severe asthama (baseline FEV1 less than 25% predicted on presentation) but not in the moderate (baseline FEV1 25% to 75% predicted on presentation) or placebo groups.
Infants, Children, and Adolescents: 25 to 75 mg/kg/dose (Max: 2 g/dose) IV as a single dose over 15 to 30 minutes. Higher doses (100 mg/kg/dose) have also been reported in children. Asthma guidelines recommend adjunct therapies, such as intravenous magnesium, in patients presenting with life-threatening exacerbations and in those with severe exacerbations that are unresponsive to 1 hour of conventional therapy.
Continuous Intravenous Infusion dosage (magnesium sulfate):
Children and Adolescents weighing 30 kg or more: 50 mg/kg/dose (Max: 2 g/dose) IV loading dose over 30 minutes, then 20 mg/kg/hour (Max: 2 g/hour) continuous IV infusion, initially, based on limited data from 1 study in 40 children with refractory asthma. Titrate dose based on magnesium serum concentrations (goal 3 to 5 mg/dL), patient response, and tolerability. Continuous infusion dosing has been utilized in order to maintain a stable magnesium concentration vs. peaks and troughs associated with bolus dosing. Guidelines recommend adjunct therapies, such as intravenous magnesium, in patients presenting with life-threatening exacerbations and in those with severe exacerbations that are unresponsive to 1 hour of conventional therapy.
Infants, Children, and Adolescents weighing less than 30 kg: 50 mg/kg/dose (Max: 2 g/dose) IV loading dose over 30 minutes, then 25 mg/kg/hour continuous IV infusion, initially, based on limited data from 1 study in 40 children with refractory asthma. Titrate dose based on magnesium serum concentrations (goal 3 to 5 mg/dL), patient response, and tolerability. Continuous infusion dosing has been utilized in order to maintain a stable magnesium concentration vs. peaks and troughs associated with bolus dosing. Guidelines recommend adjunct therapies, such as intravenous magnesium, in patients presenting with life-threatening exacerbations and in those with severe exacerbations that are unresponsive to 1 hour of conventional therapy.
Respiratory (Inhalation) dosage (isotonic magnesium sulfate, prepared from injectable formulation):
Children and Adolescents 2 to 17 years: Limited data available. 150 mg/dose inhaled by nebulizer every 20 minutes as needed for 3 doses may be considered as an adjuvant to conventional therapy when mixed with nebulized albuterol and ipratropium in the first hour of treatment for patients with acute severe asthma, particularly those with symptoms lasting less than 6 hours. In a large randomized, placebo-controlled trial (n = 508; age range: 2 to 16 years), those receiving adjuvant nebulized isotonic magnesium sulfate (n = 252) showed a statistically significant, but clinically insignificant improvement in mean Asthma Severity Score at 60 minutes. The greatest clinical response was seen in children with more severe attacks (SaO2 less than 92%) and those with symptoms present for less than 6 hours.

For perinatal neuroprotection* during premature labor*:
Intravenous dosage (magnesium sulfate):
Adults: 4 g IV over 15 to 30 minutes or 6 g IV over 20 to 30 minutes, followed by 1 to 2 g/hour continuous IV infusion until delivery or for 12 to 24 hours. Consider repeated treatment if labor stops and starts again later. Accumulated available evidence suggests that magnesium sulfate reduces the severity and risk of cerebral palsy in surviving infants.
Adolescents: 4 g IV over 15 to 30 minutes or 6 g IV over 20 to 30 minutes, followed by 1 to 2 g/hour continuous IV infusion until delivery or for up to 12 to 24 hours. Consider repeated treatment if labor stops and starts again later. Accumulated available evidence suggests that magnesium sulfate reduces the severity and risk of cerebral palsy in surviving infants.

For the treatment of seizures associated with severe toxemia of pregnancy (i.e., preeclampsia, eclampsia):
Intravenous or Intramuscular dosage (magnesium sulfate):
Adults: 4 to 6 g IV loading dose, followed by 1 to 2 g/hour continuous IV infusion for at least 24 hours. A 2 g IV bolus may be administered for recurrent seizures. Alternately, 4 to 5 g IV with simultaneous 10 g IM loading dose, followed by 1 to 2 g/hour continuous IV infusion or 4 to 5 g IM every 4 hours until seizures cease. Max: 30 to 40 g/24 hours.
Adolescents: 4 to 6 g IV loading dose, followed by 1 to 2 g/hour continuous IV infusion for at least 24 hours. A 2 g IV bolus may be administered for recurrent seizures. Alternately, 4 to 5 g IV with simultaneous 10 g IM loading dose, followed by 1 to 2 g/hour continuous IV infusion or 4 to 5 g IM every 4 hours until seizures cease. Max: 30 to 40 g/24 hours.

For eclampsia prophylaxis* or seizure prophylaxis* in preeclampsia with severe features:
Intravenous dosage (magnesium sulfate):
Adults: 4 to 6 g IV loading dose, followed by 1 to 2 g/hour continuous IV infusion for at least 24 hours. Max: 30 to 40 g/24 hours.
Adolescents: 4 to 6 g IV loading dose, followed by 1 to 2 g/hour continuous IV infusion for at least 24 hours. Max: 30 to 40 g/24 hours.
Intramuscular dosage (magnesium sulfate):
Adults: 10 g IM loading dose, followed by 5 g IM every 4 hours for at least 24 hours. Max: 30 to 40 g/24 hours.
Adolescents: 10 g IM loading dose, followed by 5 g IM every 4 hours for at least 24 hours. Max: 30 to 40 g/24 hours.

For the treatment of persistent pulmonary hypertension of the newborn* (PPHN) in mechanically ventilated neonates:
Intravenous dosage (magnesium sulfate):
Premature Neonates 33 weeks gestational age and older and Term Neonates: 200 mg/kg IV loading dose over 20 to 30 minutes followed by a continuous infusion of 20 to 150 mg/kg/hour IV titrated to maintain blood magnesium concentrations within the general range of 3 to 5.5 mmol/L (target range varies among studies) has been effective in small studies. One small randomized study reported targeting a higher serum magnesium range of 5 to 7 mmol/L. In addition to respiratory status, carefully monitor serum electrolytes, renal function, heart rate, and blood pressure during magnesium therapy.
Premature Neonates 29 to 32 weeks gestational age: 200 mg/kg IV loading dose over 20 to 30 minutes followed by a continuous infusion of 20 to 50 mg/kg/hour IV was used in a small prospective, nonrandomized trial of 7 premature neonates (birth weight 1,232 to 2,346 g). Serum magnesium concentrations ranged from 2.75 to 6.63 mmol/L during magnesium therapy. Other reports that include neonates born before 33 weeks gestation as well as neonates of older gestational ages reported loading doses of 200 mg/kg IV followed by infusions of 20 to 150 mg/kg/hour titrated to maintain blood magnesium concentrations in the general range of 3 to 5.5 mmol/L. In addition to respiratory status, carefully monitor serum electrolytes, renal function, heart rate, and blood pressure during magnesium therapy.

For the management of nephritis-associated seizures and/or nephritis-associated hypertension related to acute nephritis:
Intravenous or Intramuscular dosage (magnesium sulfate):
Infants, Children, and Adolescents: 20 to 40 mg/kg/dose (Max: 2 g/dose) IV or IM as needed to control seizures. If giving IM, a 20% solution is recommended. Data for this use in children are lacking.

For use as a laxative to treat constipation or as bowel preparation prior to surgery or radiologic, proctoscopic, or sigmoidoscopic procedures:
NOTE: See separate Magnesium Citrate monograph for dosing information.
Oral dosage (magnesium oxide):
Adults: 2 to 4 g PO at bedtime with a full glass of water.
Oral dosage (magnesium sulfate):
Adults, Adolescents, and Children 12 years and older: 10 to 30 g PO as a single dose or in divided doses.
Children 6 to 11 years: 5 to 10 g PO as a single dose or in divided doses.
Children 2 to 5 years of age: 2.5 to 5 g PO as a single dose or in divided doses.

For the treatment of dyspepsia:
Oral dosage (magnesium oxide):
Adults: 140 mg PO 3 to 4 times per day (capsules) or 400 to 840 mg/day PO (tablets).

For the treatment of muscle spasm* and dysautonomia* due to tetanus*:
Intravenous dosage (magnesium sulfate):
Adults weighing more than 45 kg: 40 or 75 mg/kg (Max: 5 g) IV once, then 2 to 3 g/hour continuous IV infusion until spasm control. Monitor patellar reflex and decrease dose if areflexia occurs.
Adults weighing 45 kg or less: 40 or 75 mg/kg IV once, then 1.5 to 3 g/hour continuous IV infusion until spasm control. Monitor patellar reflex and decrease dose if areflexia occurs.
Infants, Children, and Adolescents: 100 mg/kg IV once, then 40 mg/kg/hour continuous IV infusion; may titrate by 5 mg/kg/hour every 6 hours until spasm control and to maintain serum magnesium concentrations of 2.5 to 5 mmol/L. Max: 100 mg/kg/hour. Monitor patellar reflex and decrease dose if areflexia occurs. Lower infusion rates of 4 to 17 mg/kg/hour have also been used successfully.
Neonates: 50 mg/kg IV once, then 30 to 50 mg/kg/hour continuous IV infusion until spasm control and to maintain serum magnesium concentrations of 1 to 2.5 mmol/L. Monitor patellar reflex and decrease dose if areflexia occurs.

For the treatment of multifocal atrial tachycardia*:
Intravenous dosage (magnesium sulfate):
Adults: 2 g IV once, then 10 g in 500 mL of 5% Dextrose Injection IV over 5 hours. Guidelines suggest intravenous magnesium may be helpful in patients with multifocal atrial tachycardia, including those with normal magnesium serum concentrations.

For the acute treatment of migraine* with aura:
Intravenous dosage:
Adults: 1 to 2 g IV as a single dose. Guidelines classify intravenous magnesium sulfate as having probable efficacy for the treatment of acute migraine with aura.

Therapeutic Drug Monitoring:
-Normal serum magnesium 1.4 to 2 mEq/L; may vary depending upon laboratory standards.
-Laboratory monitoring: serum magnesium, serum potassium, and serum creatinine. Serum calcium in some circumstances.
-Other: deep tendon reflexes, respirations, and urinary output.

Maximum Dosage Limits:
The following apply to the normal dietary intake or dietary supplement intake of magnesium in healthy persons:
-Adults
Tolerable upper intake level for supplemental use is 350 mg/day PO elemental magnesium.
-Elderly
Tolerable upper intake level for supplemental use is 350 mg/day PO elemental magnesium.
-Adolescents
Tolerable upper intake level for supplemental use is 350 mg/day PO elemental magnesium.
-Children
>= 9 years: Tolerable upper intake level for supplemental use is 350 mg/day PO elemental magnesium.
4-8 years: Tolerable upper intake level for supplemental use is 110 mg/day PO elemental magnesium.
1-3 years: Tolerable upper intake level for supplemental use is 65 mg/day PO elemental magnesium.
-Infants
Safe maximum level of daily nutrient intake has not been determined.

Patients with Hepatic Impairment Dosing
Specific guidelines for dosage adjustments in hepatic impairment are not available; it appears that no dosage adjustments are needed.

Patients with Renal Impairment Dosing
Magnesium is eliminated entirely in the kidneys. Dosage should be modified depending on clinical response and degree of renal impairment, but no quantitative recommendations are available.

Intermittent hemodialysis
Dosage should be modified depending on clinical response, degree of renal impairment, and frequency of hemodialysis; no quantitative recommendations are available.

*non-FDA-approved indication

Abacavir; Dolutegravir; Lamivudine: (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain magnesium and calcium which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir. (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain magnesium which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir.

Acalabrutinib: (Moderate) Separate the administration of acalabrutinib capsules and antacids by at least 2 hours if these agents are used together. Acalabrutinib capsules solubility decreases with increasing pH values; therefore, coadministration may result in decreased acalabrutinib exposure and effectiveness. In healthy subjects, the AUC of acalabrutinib was decreased by 53% when acalabrutinib was coadministered with another antacid.

Acetaminophen: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Aspirin, ASA; Caffeine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Aspirin: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Aspirin; Diphenhydramine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Caffeine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Caffeine; Dihydrocodeine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Caffeine; Pyrilamine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Chlorpheniramine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Chlorpheniramine; Dextromethorphan: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Chlorpheniramine; Phenylephrine : (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Codeine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Dextromethorphan: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Dextromethorphan; Doxylamine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Dextromethorphan; Guaifenesin; Phenylephrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Dextromethorphan; Guaifenesin; Pseudoephedrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Dextromethorphan; Phenylephrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Dextromethorphan; Pseudoephedrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Diphenhydramine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Guaifenesin; Phenylephrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Hydrocodone: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Ibuprofen: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Oxycodone: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Pamabrom; Pyrilamine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Phenylephrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetaminophen; Pseudoephedrine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Acetazolamide: (Moderate) Diuretics may interfere with the kidneys ability to regulate magnesium concentrations. Long-term use of diuretics may impair the magnesium-conserving ability of the kidneys and lead to hypomagnesemia. (Minor) Diuretics may interfere with the kidneys ability to regulate magnesium concentrations. Long-term use of diuretics may impair the magnesium-conserving ability of the kidneys and lead to hypomagnesemia.

Acetohydroxamic Acid: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers.

Acidifying Agents: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers.

Albuterol; Budesonide: (Moderate) Enteric-coated budesonide granules dissolve at a pH more than 5.5. Likewise, the dissolution of the coating of extended-release budesonide tablets (Uceris) is pH dependent. Concomitant use of oral budesonide and antacids, milk, or other drugs that increase gastric pH levels can cause the coating of the granules to dissolve prematurely, possibly affecting release properties and absorption of the drug in the duodenum. In general, it may be prudent to avoid drugs such as antacids in combination with enteric-coated budesonide.

Alendronate: (Moderate) Separate administration of alendronate and magnesium-containing supplements by at least 30 minutes. Magnesium will interfere with the absorption of alendronate.

Alendronate; Cholecalciferol: (Major) Avoid vitamin D coadministration with magnesium-containing products, such as antacids, in persons on chronic hemodialysis due to the risk for hypermagnesemia. (Moderate) Separate administration of alendronate and magnesium-containing supplements by at least 30 minutes. Magnesium will interfere with the absorption of alendronate.

Amlodipine; Benazepril: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Amphetamine: (Minor) Monitor for an increase in amphetamine-related adverse effects during concomitant antacid use. Increasing gastric or urine pH may increase amphetamine exposure and the risk for side effects in some patients. As antacids have rarely been observed to increase gastric or urinary pH above 6.5, antacid-related pH changes may be insufficient to warrant clinical concern in most patients.

Amphetamine; Dextroamphetamine: (Minor) Monitor for an increase in amphetamine-related adverse effects during concomitant antacid use. Increasing gastric or urine pH may increase amphetamine exposure and the risk for side effects in some patients. As antacids have rarely been observed to increase gastric or urinary pH above 6.5, antacid-related pH changes may be insufficient to warrant clinical concern in most patients.

Amphetamines: (Minor) Monitor for an increase in amphetamine-related adverse effects during concomitant antacid use. Increasing gastric or urine pH may increase amphetamine exposure and the risk for side effects in some patients. As antacids have rarely been observed to increase gastric or urinary pH above 6.5, antacid-related pH changes may be insufficient to warrant clinical concern in most patients.

Angiotensin-converting enzyme inhibitors: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Anticholinergics: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Ascorbic Acid, Vitamin C: (Minor) Because antacids can alkalinize the urine, they can interact with urinary acidifiers, such as ascorbic acid. Frequent use of high doses of antacids should be avoided by patients receiving urinary acidifiers.

Aspirin, ASA; Caffeine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Atazanavir: (Major) It is recommended that antacids not be given at the some time as atazanavir because of potential interference with absorption of atazanavir. Separate the administration of atazanavir and antacids to avoid the potential for interaction; give atazanavir 2 hours before or 1 hour after the antacid.

Atazanavir; Cobicistat: (Major) It is recommended that antacids not be given at the some time as atazanavir because of potential interference with absorption of atazanavir. Separate the administration of atazanavir and antacids to avoid the potential for interaction; give atazanavir 2 hours before or 1 hour after the antacid.

Atracurium: (Moderate) Concomitant use of neuromuscular blockers and magnesium may prolong neuromuscular blockade. The use of a peripheral nerve stimulator is strongly recommended to evaluate the level of neuromuscular blockade, to assess the need for additional doses of neuromuscular blocker, and to determine whether adjustments need to be made to the dose with subsequent administration.

Atropine: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Atropine; Difenoxin: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Azithromycin: (Moderate) Separate administration of immediate-release azithromycin and aluminum- and magnesium-containing antacids by 2 hours. Coadministration may decrease the absorption of azithromycin which may decrease its efficacy. The extended-release suspension may be taken without regard to antacids containing aluminum or magnesium.

Baloxavir Marboxil: (Major) Do not administer baloxavir with products that contain magnesium carbonate. Polyvalent cations, such as magnesium, can chelate with baloxavir, reducing its absorption.

Belladonna; Opium: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Bempedoic Acid; Ezetimibe: (Minor) Antacids may decrease the peak plasma concentration (Cmax) of total ezetimibe by 30%. The effect of the antacids in this regard is not expected to have a significant effect on the ability of ezetimibe to lower cholesterol. However, to limit any potential interaction, it would be prudent to administer ezetimibe at least 1 hour before or 2 hours after administering antacids.

Benazepril: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Benazepril; Hydrochlorothiazide, HCTZ: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Benzhydrocodone; Acetaminophen: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Major) The therapeutic action of methenamine requires an acidic urine. Antacids containing alkalinizing agents such as sodium bicarbonate can alkalinize the urine, thereby decreasing the effectiveness of methenamine by increasing the amount of non-ionized drug available for renal tubular reabsorption. Increased urine alkalinity also can inhibit the conversion of methenamine to formaldehyde, which is the active bacteriostatic form; concurrent use of methenamine and urinary alkalizers is not recommended. (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Benzphetamine: (Minor) Monitor for an increase in amphetamine-related adverse effects during concomitant antacid use. Increasing gastric or urine pH may increase amphetamine exposure and the risk for side effects in some patients. As antacids have rarely been observed to increase gastric or urinary pH above 6.5, antacid-related pH changes may be insufficient to warrant clinical concern in most patients.

Benztropine: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Bictegravir; Emtricitabine; Tenofovir Alafenamide: (Moderate) Administer bictegravir on an empty stomach 2 hours before or 6 hours after taking antacids containing aluminum or magnesium. Routine administration of bictegravir simultaneously with, or 2 hours after, antacids containing aluminum or magnesium is not recommended as the bioavailability of bictegravir may be reduced. In drug interaction studies, simultaneous administration of bictegravir and antacids under fasted and fed conditions decreased the mean AUC of bictegravir by approximately 79% and 47%, respectively. (Moderate) Administer bictegravir on an empty stomach 2 hours before or 6 hours after taking oral medications containing magnesium. Routine administration of bictegravir simultaneously with, or 2 hours after, oral medications containing magnesium is not recommended as the bioavailability of bictegravir may be reduced.

Bisacodyl: (Minor) The concomitant use of bisacodyl tablets with antacids can cause the enteric coating of the bisacody tablet to dissolve prematurely, leading to possible gastric irritation or dyspepsia. Avoid antacids within 1 hour before or after the bisacodyl dosage.

Bismuth Subcitrate Potassium; Metronidazole; Tetracycline: (Moderate) Administer oral magnesium-containing products at least 3 hours before or 3 hours after orally administered tetracyclines. Tetracycline absorption may be reduced as tetracycline antibiotics can chelate with divalent or trivalent cations. (Moderate) Separate administration of tetracycline and antacids by 2 to 3 hours. Coadministration may impair absorption of tetracycline which may decrease its efficacy.

Bismuth Subsalicylate; Metronidazole; Tetracycline: (Moderate) Administer oral magnesium-containing products at least 3 hours before or 3 hours after orally administered tetracyclines. Tetracycline absorption may be reduced as tetracycline antibiotics can chelate with divalent or trivalent cations. (Moderate) Separate administration of tetracycline and antacids by 2 to 3 hours. Coadministration may impair absorption of tetracycline which may decrease its efficacy.

Bosutinib: (Moderate) Bosutinib displays pH-dependent aqueous solubility; therefore, concomitant use of bosutinib and antacids may result in decreased plasma exposure of bosutinib. Separate the administration of bosutinib and antacids by more than 2 hours.

Budesonide: (Moderate) Enteric-coated budesonide granules dissolve at a pH more than 5.5. Likewise, the dissolution of the coating of extended-release budesonide tablets (Uceris) is pH dependent. Concomitant use of oral budesonide and antacids, milk, or other drugs that increase gastric pH levels can cause the coating of the granules to dissolve prematurely, possibly affecting release properties and absorption of the drug in the duodenum. In general, it may be prudent to avoid drugs such as antacids in combination with enteric-coated budesonide.

Budesonide; Formoterol: (Moderate) Enteric-coated budesonide granules dissolve at a pH more than 5.5. Likewise, the dissolution of the coating of extended-release budesonide tablets (Uceris) is pH dependent. Concomitant use of oral budesonide and antacids, milk, or other drugs that increase gastric pH levels can cause the coating of the granules to dissolve prematurely, possibly affecting release properties and absorption of the drug in the duodenum. In general, it may be prudent to avoid drugs such as antacids in combination with enteric-coated budesonide.

Budesonide; Glycopyrrolate; Formoterol: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction. (Moderate) Enteric-coated budesonide granules dissolve at a pH more than 5.5. Likewise, the dissolution of the coating of extended-release budesonide tablets (Uceris) is pH dependent. Concomitant use of oral budesonide and antacids, milk, or other drugs that increase gastric pH levels can cause the coating of the granules to dissolve prematurely, possibly affecting release properties and absorption of the drug in the duodenum. In general, it may be prudent to avoid drugs such as antacids in combination with enteric-coated budesonide.

Butalbital; Acetaminophen: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Butalbital; Acetaminophen; Caffeine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Butalbital; Acetaminophen; Caffeine; Codeine: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Cabotegravir: (Moderate) Administer antacids at least two hours before or four hours after taking oral cabotegravir. The chemical structure of these antacids contains aluminum or magnesium which can bind cabotegravir in the GI tract. Taking these drugs simultaneously may result in reduced oral bioavailability of cabotegravir. (Moderate) Administer oral magnesium oxide at least two hours before or four hours after taking oral cabotegravir. Magnesium is a polyvalent cation that can bind cabotegravir in the GI tract. Taking these drugs simultaneously may result in reduced oral bioavailability of cabotegravir.

Cabotegravir; Rilpivirine: (Moderate) Administer antacids at least two hours before or four hours after taking oral cabotegravir. The chemical structure of these antacids contains aluminum or magnesium which can bind cabotegravir in the GI tract. Taking these drugs simultaneously may result in reduced oral bioavailability of cabotegravir. (Moderate) Administer oral magnesium oxide at least two hours before or four hours after taking oral cabotegravir. Magnesium is a polyvalent cation that can bind cabotegravir in the GI tract. Taking these drugs simultaneously may result in reduced oral bioavailability of cabotegravir. (Moderate) Concurrent administration of rilpivirine and antacids may significantly decrease rilpivirine plasma concentrations, potentially resulting in treatment failure. To decrease the risk of virologic failure, avoid use of antacids for at least 2 hours before and at least 4 hours after administering rilpivirine.

Calcifediol: (Major) Avoid vitamin D analog coadministration with magnesium-containing products, such as antacids, in persons on chronic hemodialysis due to the risk for hypermagnesemia.

Calcitriol: (Major) Avoid vitamin D analog coadministration with magnesium-containing products, such as antacids, in persons on chronic hemodialysis due to the risk for hypermagnesemia.

Calcium; Vitamin D: (Major) Avoid vitamin D coadministration with magnesium-containing products, such as antacids, in persons on chronic hemodialysis due to the risk for hypermagnesemia.

Captopril: (Major) Antacids can decrease the GI absorption of captopril if administered simultaneously. (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Captopril; Hydrochlorothiazide, HCTZ: (Major) Antacids can decrease the GI absorption of captopril if administered simultaneously. (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Carbonic anhydrase inhibitors: (Moderate) Diuretics may interfere with the kidneys ability to regulate magnesium concentrations. Long-term use of diuretics may impair the magnesium-conserving ability of the kidneys and lead to hypomagnesemia. (Minor) Diuretics may interfere with the kidneys ability to regulate magnesium concentrations. Long-term use of diuretics may impair the magnesium-conserving ability of the kidneys and lead to hypomagnesemia.

Cefdinir: (Moderate) Administer cefdinir at least 2 hours before or 2 hours after magnesium chloride. Cefdinir absorption may be reduced. (Moderate) Administer cefdinir at least 2 hours before or 2 hours after magnesium gluconate. Cefdinir absorption may be reduced. (Moderate) Administer cefdinir at least 2 hours before or 2 hours after magnesium sulfate. Cefdinir absorption may be reduced. (Moderate) Antacids containing magnesium or aluminum can interfere with the absorption of cefdinir. If aluminum or magnesium containing antacids are required during cefdinir therapy, cefdinir should be taken at least 2 hours before or after the antacid.

Cefpodoxime: (Moderate) Cefpodoxime proxetil requires a low gastric pH for dissolution; therefore, concurrent administration with medications that increase gastric pH (e.g., antacids) may decrease the bioavailability of cefpodoxime. Concomitant administration with high doses of antacids reduces peak plasma concentrations by 24% and the extent of absorption by 27%. The rate of absorption is not affected.

Cefuroxime: (Moderate) Antacids can interfere with the oral absorption of cefuroxime axetil and may result in reduced antibiotic efficacy. If an antacid must be used while a patient is taking cefuroxime, administer the oral dosage of cefuroxime at least 1 hour before or 2 hours after the antacid.

Chlordiazepoxide; Clidinium: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Chloroquine: (Major) Chloroquine absorption may be reduced by antacids. Administer chloroquine and antacids at least 4 hours apart.

Chlorpromazine: (Moderate) The absorption of chlorpromazine liquids, suspensions, or concentrates may be decreased by co-administration of antacids. It may be advisable to separate chlorpromazine administration from antacids by 1 to 2 hours. In a small study (n = 6), administration of a magnesium trisilicate and aluminum hydroxide liquid gel antacid with a chlorpromazine liquid suspension resulted in a statistically significant decrease in chlorpromazine concentrations (average 20% decline; approximate range: 6% to 48%). In another kinetic study (n = 10), concurrent use of chlorpromazine liquid concentrate and an aluminum and magnesium hydroxide suspension reduced the urinary excretion of chlorpromazine by 10% to 45%. Adsorption of chlorpromazine to the antacid suspension may have contributed to a subsequent decline in urinary excretion of the drug.

Ciprofloxacin: (Moderate) Administer oral ciprofloxacin at least 2 hours before or 6 hours after magnesium carbonate. Ciprofloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. (Moderate) Administer oral ciprofloxacin at least 2 hours before or 6 hours after oral products that contain magnesium. Ciprofloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations.

Cisatracurium: (Moderate) Concomitant use of neuromuscular blockers and magnesium may prolong neuromuscular blockade. The use of a peripheral nerve stimulator is strongly recommended to evaluate the level of neuromuscular blockade, to assess the need for additional doses of neuromuscular blocker, and to determine whether adjustments need to be made to the dose with subsequent administration.

Citric Acid; Potassium Citrate; Sodium Citrate: (Contraindicated) Avoid coadministration of antacids with citrate salts since increased absorption of aluminum can occur. In addition, some antacids like calcium carbonate, share the potential with the citrate salts for development of metabolic alkalosis, when given in higher dosage.

Cod Liver Oil: (Major) Avoid vitamin D coadministration with magnesium-containing products, such as antacids, in persons on chronic hemodialysis due to the risk for hypermagnesemia.

Cysteamine: (Major) In general, cysteamine may be administered with electrolyte and mineral replacements necessary for managing Fanconi syndrome, as well as with vitamin D and thyroid hormone. However, delayed-release cysteamine (Procysbi) should be administered at least 1 hour before or 1 after medications that increase gastric pH, including those containing bicarbonate or carbonate (i.e., magnesium carbonate). Drugs that increase the gastric pH, such as bicarbonate and carbonate, may cause the premature release of cysteamine from delayed-release capsules, leading to an increase in WBC cystine concentration.

Dasatinib: (Moderate) Separate the administration of dasatinib and antacids by at least 2 hours if these agents are used together. The simultaneous administration of an antacid with dasatinib decreased the Cmax and AUC of dasatinib by 58% and 55%, respectively.

Delafloxacin: (Major) Administer oral delafloxacin at least 2 hours before or 6 hours after oral products that contain magnesium. Delafloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Examples of compounds that may interfere with quinolone bioavailability include antacids and multivitamins that contain magnesium.

Delavirdine: (Major) Coadministration of delavirdine with antacids results in decreased absorption of delavirdine. Administration of delavirdine and antacids should be separated by at least 1 hour.

Demeclocycline: (Moderate) Administer oral magnesium-containing products at least 3 hours before or 3 hours after orally administered tetracyclines. Tetracycline absorption may be reduced as tetracycline antibiotics can chelate with divalent or trivalent cations. (Moderate) Separate administration of demeclocycline and antacids by 2 to 3 hours. Coadministration may impair absorption of demeclocycline which may decrease its efficacy.

Dextroamphetamine: (Minor) Monitor for an increase in amphetamine-related adverse effects during concomitant antacid use. Increasing gastric or urine pH may increase amphetamine exposure and the risk for side effects in some patients. As antacids have rarely been observed to increase gastric or urinary pH above 6.5, antacid-related pH changes may be insufficient to warrant clinical concern in most patients.

Dextromethorphan; Quinidine: (Major) Alkalinizing agents such as antacids can increase renal tubular reabsorption of quinidine by alkalinizing the urine; higher quinidine serum concentrations and quinidine toxicity are possible.

Diazepam: (Moderate) The coadministration of diazepam with antacids results in delayed diazepam absorption due to the fact that antacids delay gastric emptying. It may be prudent to separate dosing by 2 hours to limit any potential interaction.

Dicyclomine: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Didanosine, ddI: (Minor) The side effects associated with magnesium carbonate may potentially be increased during concurrent use with didanosine, ddI because some ddI products also contain similar antacid ingredients. Although this interaction should be of minor clinical significance for most patients, clinicians should be alert to a possible increased risk of side effects associated with taking an additional antacid product concurrently with ddI products.

Diflunisal: (Moderate) Concurrent use of diflunisal with antacids may reduce plasma diflunisal concentrations. The effect may be clinically significant if antacids are used on a continuous schedule.

Digoxin: (Moderate) Monitor digoxin concentrations as appropriate and watch for decreased digoxin efficacy if coadministration with antacids is necessary. The dose of digoxin may need to be adjusted. Antacids may decrease the absorption of digoxin.

Diphenhydramine; Naproxen: (Minor) Concomitant administration of antacids can delay the absorption of naproxen. Periodic antacid use should not be problematic as long as the antacid and enteric-coated naproxen administration are separated by at least 2 hours.

Diphenoxylate; Atropine: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Dolutegravir: (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain magnesium and calcium which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir. (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain magnesium which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir.

Dolutegravir; Lamivudine: (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain magnesium and calcium which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir. (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain magnesium which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir.

Dolutegravir; Rilpivirine: (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain magnesium and calcium which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir. (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking cation-containing antacids. The chemical structure of these antacids contain magnesium which can bind dolutegravir in the GI tract. Taking these drugs simultaneously may result in reduced bioavailability of dolutegravir. (Moderate) Concurrent administration of rilpivirine and antacids may significantly decrease rilpivirine plasma concentrations, potentially resulting in treatment failure. To decrease the risk of virologic failure, avoid use of antacids for at least 2 hours before and at least 4 hours after administering rilpivirine.

Doxercalciferol: (Major) Avoid vitamin D analog coadministration with magnesium-containing products, such as antacids, in persons on chronic hemodialysis due to the risk for hypermagnesemia.

Doxycycline: (Moderate) Administer oral magnesium-containing products at least 3 hours before or 3 hours after orally administered tetracyclines. Tetracycline absorption may be reduced as tetracycline antibiotics can chelate with divalent or trivalent cations. (Moderate) Separate administration of oral doxycycline and antacids by 2 to 3 hours. Coadministration may impair absorption of doxycycline which may decrease its efficacy.

Edetate Calcium Disodium, Calcium EDTA: (Major) Administration of oral magnesium with edetate disodium, disodium EDTA may result in binding of magnesium. Do not administer oral magnesium salts within 1 hour of edetate disodium, EDTA.

Eltrombopag: (Major) Eltrombopag chelates polyvalent cations (e.g., calcium, aluminum, and magnesium) in food, mineral supplements, and antacids. In a clinical study, systemic exposure to eltrombopag was decreased by 70% when it was administered with a polyvalent cation-containing antacid. Administer eltrombopag at least 2 hours before or 4 hours after any oral products containing polyvalent cations, such as aluminum salts, (like aluminum hydroxide), calcium salts, (including calcium carbonate), and magnesium salts.

Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide: (Moderate) Separate administration of elvitegravir and antacids by at least 2 hours. Due to the formation of ionic complexes in the gastrointestinal tract, simultaneous administration results in lower elvitegravir plasma concentrations.

Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) Separate administration of elvitegravir and antacids by at least 2 hours. Due to the formation of ionic complexes in the gastrointestinal tract, simultaneous administration results in lower elvitegravir plasma concentrations.

Emtricitabine; Rilpivirine; Tenofovir alafenamide: (Moderate) Concurrent administration of rilpivirine and antacids may significantly decrease rilpivirine plasma concentrations, potentially resulting in treatment failure. To decrease the risk of virologic failure, avoid use of antacids for at least 2 hours before and at least 4 hours after administering rilpivirine.

Emtricitabine; Rilpivirine; Tenofovir Disoproxil Fumarate: (Moderate) Concurrent administration of rilpivirine and antacids may significantly decrease rilpivirine plasma concentrations, potentially resulting in treatment failure. To decrease the risk of virologic failure, avoid use of antacids for at least 2 hours before and at least 4 hours after administering rilpivirine.

Enalapril, Enalaprilat: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Enalapril; Hydrochlorothiazide, HCTZ: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Erlotinib: (Major) Separate administration by several hours if concomitant use of erlotinib and antacids is necessary. Erlotinib displays pH-dependent solubility with decreased solubility at a higher pH; the increased gastric pH resulting from antacid therapy may reduce the bioavailability of erlotinib. Increasing the dose of erlotinib without modifying the administration schedule is unlikely to compensate for loss of exposure. The effects of antacids on erlotinib pharmacokinetics has not been evaluated.

Etidronate: (Moderate) Do not administer any oral magnesium-containing products within 2 hours of etidronate; oral magnesium may significantly reduce the absorption of etidronate. Some recommend that divalent cation-containing products should preferentially be taken at least 2 hours after any oral bisphosphonates or at a completely different time of day.

Ezetimibe: (Minor) Antacids may decrease the peak plasma concentration (Cmax) of total ezetimibe by 30%. The effect of the antacids in this regard is not expected to have a significant effect on the ability of ezetimibe to lower cholesterol. However, to limit any potential interaction, it would be prudent to administer ezetimibe at least 1 hour before or 2 hours after administering antacids.

Ezetimibe; Simvastatin: (Minor) Antacids may decrease the peak plasma concentration (Cmax) of total ezetimibe by 30%. The effect of the antacids in this regard is not expected to have a significant effect on the ability of ezetimibe to lower cholesterol. However, to limit any potential interaction, it would be prudent to administer ezetimibe at least 1 hour before or 2 hours after administering antacids.

Ferric Maltol: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.

Fexofenadine: (Moderate) Coadministration with antacids (containing aluminum or magnesium) within 15 minutes decreases the AUC and Cmax of fexofenadine by 41% and 43%, respectively. Separate administration is recommended.

Fexofenadine; Pseudoephedrine: (Moderate) Coadministration with antacids (containing aluminum or magnesium) within 15 minutes decreases the AUC and Cmax of fexofenadine by 41% and 43%, respectively. Separate administration is recommended.

Flavoxate: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Fosamprenavir: (Moderate) Administer fosamprenavir at least 1 hour before or 1 hour after antacids. Coadministration may decrease the exposure of fosamprenavir and impair its efficacy.

Fosinopril: (Moderate) Coadministration of antacids with fosinopril may impair absorption of fosinopril. Therefore, if concomitant administration of these agents is indicated, dosing should be separated by 2 hours. (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Fosinopril; Hydrochlorothiazide, HCTZ: (Moderate) Coadministration of antacids with fosinopril may impair absorption of fosinopril. Therefore, if concomitant administration of these agents is indicated, dosing should be separated by 2 hours. (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Gabapentin: (Moderate) Gabapentin should be taken at least 2 hours after the administration of antacids. Antacids have been shown to reduce the oral bioavailability of gabapentin by roughly 20%. This decrease in bioavailability was about 5% when gabapentin was administered 2 hours after the antacid.

Gastrointestinal Enzymes: (Major) The effectiveness of gastrointestinal enzymes can be diminished with concurrent administration of antacids. In-vitro studies suggest that calcium and magnesum cations exert their deleterious effect on replacement enzyme therapy by formation of poorly soluble calcium or magnesium soaps and precipitation of glycine conjugated bile salts.

Gefitinib: (Major) Avoid coadministration of antacids with gefitinib if possible due to decreased exposure to gefitinib, which may lead to reduced efficacy. If concomitant use is unavoidable, take gefitinib 6 hours after the last dose or 6 hours before the next antacid dose. Gefitinib exposure is affected by gastric pH. Coadministration with another drug to maintain gastric pH above 5 decreased gefitinib exposure by 47%.

Gemifloxacin: (Major) Administer oral products that contain magnesium at least 3 hours before or 2 hours after gemifloxacin. Gemifloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Examples of compounds that may interfere with quinolone bioavailability include antacids and multivitamins that contain magnesium. (Major) Unlike most oral quinolones, oral gemifloxacin may be administered without regard to food; calcium does not appear to appreciably affect the bioavailability of the oral dosage form. Most quinolones are susceptible to oral chelation interactions with selected cations. The oral absorption of gemifloxacin may be significantly reduced by other orally administered multivalent cations such as aluminum salts (e.g., aluminum hydroxide) and magnesium salts. Examples of compounds that may interfere with fluoroquinolone bioavailability include most antacids (including combination antacids containing aluminum or magnesium, but not calcium carbonate); magnesium citrate; magnesium salicylate; and multivitamins that contain magnesium. Calcium carbonate (1000 mg) given either 2 hr before or 2 hr after gemifloxacin administration did not notably reduce oral gemifloxacin systemic availability. Calcium carbonate administered simultaneously with gemifloxacin resulted in a small, but not clinically significant, decrease in gemifloxacin AUC by 21% and Cmax. Significant pharmacokinetic interactions can occur when Maalox (aluminum hydroxide; magnesium hydroxide) is administered with gemifloxacin. Maalox given 10 minutes before gemifloxacin reduced the gemifloxacin AUC by approximately 85%; Maalox 3 hours after gemifloxacin resulted in a 15% gemifloxacin AUC reduction. No effect on gemifloxacin AUC was observed when Maalox was given 2 hours before the antimicrobial agent. It is not yet clear if bismuth subsalicylate (Pepto-Bismol) can interfere with fluoroquinolone bioavailability. To help avoid interactions due to chelation, gemifloxacin should be taken at least 3 hours before or 2 hours after administration of a potential interfering agent.

Glipizide: (Moderate) Antacids have been reported to increase the absorption of glipizide, enhancing its hypoglycemic effects. Although the exact mechanism is not known, theoretically it may be due to alterations in gastric pH. If these drugs must be used together, give glipizide at least 2 hours prior to the antacid. Consider closely monitoring blood glucose concentrations.

Glipizide; Metformin: (Moderate) Antacids have been reported to increase the absorption of glipizide, enhancing its hypoglycemic effects. Although the exact mechanism is not known, theoretically it may be due to alterations in gastric pH. If these drugs must be used together, give glipizide at least 2 hours prior to the antacid. Consider closely monitoring blood glucose concentrations.

Glyburide: (Moderate) Antacids have been reported to increase the absorption of non-micronized glyburide, enhancing their hypoglycemic effects. Although the exact mechanism is not known, theoretically it may be due to alterations in gastric pH. If antacids must be used while a patient is taking glyburide, give the glyburide at least 2 hours prior to the antacid. Consider closely monitoring blood glucose concentrations.

Glyburide; Metformin: (Moderate) Antacids have been reported to increase the absorption of non-micronized glyburide, enhancing their hypoglycemic effects. Although the exact mechanism is not known, theoretically it may be due to alterations in gastric pH. If antacids must be used while a patient is taking glyburide, give the glyburide at least 2 hours prior to the antacid. Consider closely monitoring blood glucose concentrations.

Glycopyrrolate: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Glycopyrrolate; Formoterol: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Homatropine; Hydrocodone: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Hydrochlorothiazide, HCTZ; Moexipril: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Hydroxychloroquine: (Moderate) Hydroxychloroquine absorption may be reduced by antacids as has been observed with the structurally similar chloroquine. Administer hydroxychloroquine and antacids at least 4 hours apart. Of note, a study demonstrated no significant difference in hydroxychloroquine serum concentration in patients taking concomitant antacids (n = 14) compared to those not taking antacids (n = 495).

Hyoscyamine: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate; Sodium Biphosphate: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Major) The therapeutic action of methenamine requires an acidic urine. Antacids containing alkalinizing agents such as sodium bicarbonate can alkalinize the urine, thereby decreasing the effectiveness of methenamine by increasing the amount of non-ionized drug available for renal tubular reabsorption. Increased urine alkalinity also can inhibit the conversion of methenamine to formaldehyde, which is the active bacteriostatic form; concurrent use of methenamine and urinary alkalizers is not recommended. (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Ibandronate: (Moderate) Magnesium-containing products may significantly reduce the absorption of ibandronate. All medications should be administered at least 60 minutes after an ibandronate dose to help prevent these absorption interactions. However, some recommend that divalent cation-containing products should preferentially be taken at least 2 hours after ibandronate or at a completely different time of day.

Ibritumomab Tiuxetan: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products.

Indacaterol; Glycopyrrolate: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Indomethacin: (Moderate) Antacids may inhibit the oral absorption of indomethacin. Simultaneous administration should be avoided; separate dosing by at least 2 hours to limit an interaction.

Infigratinib: (Moderate) Separate the administration of infigratinib and locally acting antacids if concomitant use is necessary. Coadministration may decrease infigratinib exposure resulting in decreased efficacy. Administer infigratinib two hours before or after an antacid.

Iron Salts: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.

Iron: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.

Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Moderate) Concomitant use of antacids and rifampin may decrease the absorption of rifampin. Daily doses of rifampin should be given at least 1 hour before the ingestion of antacids.

Isoniazid, INH; Rifampin: (Moderate) Concomitant use of antacids and rifampin may decrease the absorption of rifampin. Daily doses of rifampin should be given at least 1 hour before the ingestion of antacids.

Itraconazole: (Moderate) When administering antacids with the 100 mg itraconazole capsule and 200 mg itraconazole tablet formulations, systemic exposure to itraconazole is decreased. Conversely, exposure to itraconazole is increased when antacids are administered with the 65 mg itraconazole capsule. Administer antacids at least 2 hours before or 2 hours after the 100 mg capsule or 200 mg tablet. Monitor for increased itraconazole-related adverse effects if antacids are administered with itraconazole 65 mg capsules.

Ketoconazole: (Moderate) Administer antacids at least 1 hour before or 2 hours after taking ketoconazole. Antacids can impair the absorption of ketoconazole.

Lactulose: (Major) In general, other laxatives should not be used concurrently with lactulose, especially during the initial phase of therapy for portal-systemic encephalopathy, because the loose stools resulting from their use may falsely suggest that adequate lactulose dosage has been achieved. Studies suggest that oral, nonabsorbable antacids and/or laxatives like magnesium hydroxide can interfere with the decrease in colon pH necessary for lactulose's action and these alterations may make it challenging to titrate an accurate dose of lactulose during treatment of hepatic encephalopathy. (Major) In general, other laxatives, such as magnesium sulfate, should not be used concurrently with lactulose, especially during the initial phase of therapy for portal-systemic encephalopathy, because the loose stools resulting from their use may falsely suggest that adequate lactulose dosage has been achieved.

Ledipasvir; Sofosbuvir: (Moderate) Separate administration of ledipasvir and antacids by at least 4 hours. Solubility of ledipasvir decreases as gastric pH increases; thus, simultaneous administration of these drugs may result in lower ledipasvir plasma concentrations.

Levofloxacin: (Moderate) Administer magnesium carbonate at least 2 hours before or 2 hours after orally administered levofloxacin. Levofloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Chelation of divalent cations with levofloxacin is less than with other quinolones. (Moderate) Administer oral products that contain magnesium at least 2 hours before or 2 hours after orally administered levofloxacin. Levofloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Chelation of divalent cations with levofloxacin is less than with other quinolones.

Levoketoconazole: (Moderate) Administer antacids at least 1 hour before or 2 hours after taking ketoconazole. Antacids can impair the absorption of ketoconazole.

Levonorgestrel; Ethinyl Estradiol; Ferrous Bisglycinate: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.

Levonorgestrel; Ethinyl Estradiol; Ferrous Fumarate: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.

Levothyroxine: (Moderate) Administer thyroid hormones at least 4 hours before or after antacids, dietary supplements, or other drugs containing magnesium. Magnesium salts have been reported to chelate oral thyroid hormones within the GI tract when administered simultaneously, leading to decreased thyroid hormone absorption. Some case reports have described clinical hypothyroidism resulting from coadministration of levothyroxine with products containing oral cations, such as antacids or dietary supplements.

Levothyroxine; Liothyronine (Porcine): (Moderate) Administer thyroid hormones at least 4 hours before or after antacids, dietary supplements, or other drugs containing magnesium. Magnesium salts have been reported to chelate oral thyroid hormones within the GI tract when administered simultaneously, leading to decreased thyroid hormone absorption. Some case reports have described clinical hypothyroidism resulting from coadministration of levothyroxine with products containing oral cations, such as antacids or dietary supplements.

Levothyroxine; Liothyronine (Synthetic): (Moderate) Administer thyroid hormones at least 4 hours before or after antacids, dietary supplements, or other drugs containing magnesium. Magnesium salts have been reported to chelate oral thyroid hormones within the GI tract when administered simultaneously, leading to decreased thyroid hormone absorption. Some case reports have described clinical hypothyroidism resulting from coadministration of levothyroxine with products containing oral cations, such as antacids or dietary supplements.

Liothyronine: (Moderate) Administer thyroid hormones at least 4 hours before or after antacids, dietary supplements, or other drugs containing magnesium. Magnesium salts have been reported to chelate oral thyroid hormones within the GI tract when administered simultaneously, leading to decreased thyroid hormone absorption. Some case reports have described clinical hypothyroidism resulting from coadministration of levothyroxine with products containing oral cations, such as antacids or dietary supplements.

Lisdexamfetamine: (Minor) Monitor for an increase in amphetamine-related adverse effects during concomitant antacid use. Increasing gastric or urine pH may increase amphetamine exposure and the risk for side effects in some patients. As antacids have rarely been observed to increase gastric or urinary pH above 6.5, antacid-related pH changes may be insufficient to warrant clinical concern in most patients.

Lisinopril: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Lisinopril; Hydrochlorothiazide, HCTZ: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Mannitol: (Moderate) Diuretics may interfere with the kidneys ability to regulate magnesium concentrations. Long-term use of diuretics may impair the magnesium-conserving ability of the kidneys and lead to hypomagnesemia.

Mefenamic Acid: (Moderate) Ingestion of mefenamic acid with antacids is not recommended. Administration with an antacid containing 1.7 grams of magnesium hydroxide resulted in a 36 percent increase in the area under the time versus concentration curve of mefenamic acid.

Mefloquine: (Moderate) Antacids, H2-blockers, and proton pump inhibitors (PPIs) may increase plasma concentrations of mefloquine. In a small study involving 6 healthy subjects and 6 peptic ulcer patients, cimetidine increased the Cmax and AUC of mefloquine. In the study, the pharmacokinetics of mefloquine were determined after receiving a single oral mefloquine 500 mg dose alone and after 3-days of cimetidine 400 mg PO bid. In both healthy subjects and peptic ulcer patients, Cmax was increased 42.4% and 20.5%, respectively. The AUC was increased by 37.5% in both groups. Elimination half-life, total clearance, and volume of distribution were not significantly affected. An increase in adverse reactions was not noted. Patients on chronic mefloquine therapy might be at increased risk of adverse reactions, especially in patients with a neurological or psychiatric history.

Mesalamine, 5-ASA: (Moderate) Do not coadminister mesalamine extended-release capsules (Apriso) with antacids. Apriso is a pH-dependent, delayed-release capsule product with an enteric coating that dissolves at a pH of at least 6. Other mesalamine products do not have an interaction with antacids.

Methamphetamine: (Minor) Monitor for an increase in amphetamine-related adverse effects during concomitant antacid use. Increasing gastric or urine pH may increase amphetamine exposure and the risk for side effects in some patients. As antacids have rarely been observed to increase gastric or urinary pH above 6.5, antacid-related pH changes may be insufficient to warrant clinical concern in most patients.

Methazolamide: (Moderate) Diuretics may interfere with the kidneys ability to regulate magnesium concentrations. Long-term use of diuretics may impair the magnesium-conserving ability of the kidneys and lead to hypomagnesemia. (Minor) Diuretics may interfere with the kidneys ability to regulate magnesium concentrations. Long-term use of diuretics may impair the magnesium-conserving ability of the kidneys and lead to hypomagnesemia.

Methenamine: (Major) The therapeutic action of methenamine requires an acidic urine. Antacids containing alkalinizing agents such as sodium bicarbonate can alkalinize the urine, thereby decreasing the effectiveness of methenamine by increasing the amount of non-ionized drug available for renal tubular reabsorption. Increased urine alkalinity also can inhibit the conversion of methenamine to formaldehyde, which is the active bacteriostatic form; concurrent use of methenamine and urinary alkalizers is not recommended.

Methenamine; Sodium Acid Phosphate; Methylene Blue; Hyoscyamine: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Major) The therapeutic action of methenamine requires an acidic urine. Antacids containing alkalinizing agents such as sodium bicarbonate can alkalinize the urine, thereby decreasing the effectiveness of methenamine by increasing the amount of non-ionized drug available for renal tubular reabsorption. Increased urine alkalinity also can inhibit the conversion of methenamine to formaldehyde, which is the active bacteriostatic form; concurrent use of methenamine and urinary alkalizers is not recommended. (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Methenamine; Sodium Salicylate: (Major) The therapeutic action of methenamine requires an acidic urine. Antacids containing alkalinizing agents such as sodium bicarbonate can alkalinize the urine, thereby decreasing the effectiveness of methenamine by increasing the amount of non-ionized drug available for renal tubular reabsorption. Increased urine alkalinity also can inhibit the conversion of methenamine to formaldehyde, which is the active bacteriostatic form; concurrent use of methenamine and urinary alkalizers is not recommended.

Methscopolamine: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Minocycline: (Moderate) Administer oral magnesium-containing products at least 3 hours before or 3 hours after orally administered tetracyclines. Tetracycline absorption may be reduced as tetracycline antibiotics can chelate with divalent or trivalent cations. (Moderate) Separate administration of minocycline and antacids by 2 to 3 hours. Coadministration may impair absorption of minocycline which may decrease its efficacy.

Moexipril: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Moxifloxacin: (Major) Administer oral moxifloxacin at least 4 hours before or 8 hours after oral products that contain magnesium. Moxifloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Examples of compounds that may interfere with quinolone bioavailability include antacids and multivitamins that contain magnesium. (Major) Similar to gatifloxacin, but unlike most fluoroquinolones, no clinically significant pharmacokinetic interactions occur when moxifloxacin is administered concomitantly with milk or calcium carbonate. In healthy volunteers, calcium supplements had no significant effect on the AUC of moxifloxacin, however, the mean Cmax was slightly reduced and the time to Cmax was prolonged compared to moxifloxacin given alone. The oral absorption of moxifloxacin may be significantly reduced by other orally administered compounds that contain aluminum salts (like aluminum hydroxide), iron salts, magnesium salts, or zinc salts. Examples of compounds that may interfere with fluoroquinolone bioavailability include antacids (e.g., aluminum hydroxide, magnesium hydroxide, or combination antacids containing aluminum or magnesium); sucralfate; magnesium citrate; magnesium salicylate; iron supplements (e.g., polysaccharide-iron complex) and multivitamins that contain iron, magnesium, manganese, or zinc. It is not yet clear if bismuth subsalicylate (Pepto-Bismol) can interfere with fluoroquinolone bioavailability. Oral moxifloxacin should be taken at least 4 hours before or 8 hours after administration of the above agents.

Mycophenolate: (Major) Coadministration of mycophenolate mofetil with antacids decreases the bioavailability of mycophenolate mofetil. Aluminum/magnesium hydroxide antacids decrease the AUC of mycophenolic acid by about 17% when given as mycophenolate mofetil. Decreased absorption of mycophenolate (possible chelation) is the likely etiology for reduced systemic exposure. If antacids and mycophenolate need to be used together, separate administration times are recommended (do not give simultaneously).

Naproxen: (Minor) Concomitant administration of antacids can delay the absorption of naproxen. Periodic antacid use should not be problematic as long as the antacid and enteric-coated naproxen administration are separated by at least 2 hours.

Naproxen; Esomeprazole: (Minor) Concomitant administration of antacids can delay the absorption of naproxen. Periodic antacid use should not be problematic as long as the antacid and enteric-coated naproxen administration are separated by at least 2 hours.

Naproxen; Pseudoephedrine: (Minor) Concomitant administration of antacids can delay the absorption of naproxen. Periodic antacid use should not be problematic as long as the antacid and enteric-coated naproxen administration are separated by at least 2 hours.

Neostigmine; Glycopyrrolate: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Neratinib: (Major) Administer neratinib at least 3 hours after administration of antacids if concomitant use is necessary due to decreased absorption and systemic exposure of neratinib; the solubility of neratinib decreases with increasing pH of the GI tract. The efficacy of neratinib may be decreased.

Neuromuscular blockers: (Moderate) Concomitant use of neuromuscular blockers and magnesium may prolong neuromuscular blockade. The use of a peripheral nerve stimulator is strongly recommended to evaluate the level of neuromuscular blockade, to assess the need for additional doses of neuromuscular blocker, and to determine whether adjustments need to be made to the dose with subsequent administration.

NIFEdipine: (Major) Clinically significant drug interactions including neuromuscular blockade and hypotension have occurred when IV magnesium salts were given concurrently with nifedipine during the treatment of hypertension or premature labor during pregnancy. The effects have been attributed to nifedipine potentiation of the neuromuscular blocking effects of magnesium. It is recommended that nifedipine not be given concurrently with magnesium therapy for pre-eclampsia, hypertension, or tocolytic treatment during pregnancy.

Nilotinib: (Moderate) If concomitant use of these agents is necessary, administer the antacid approximately 2 hours before or approximately 2 hours after the nilotinib dose. Nilotinib displays pH-dependent solubility with decreased solubility at a higher pH; therefore, concomitant use of nilotinib and antacids may result in decreased bioavailability of nilotinib. In a study in healthy subjects, there was no significant change in nilotinib pharmacokinetics when an antacid (aluminum hydroxide/magnesium hydroxide/simethicone) was administered approximately 2 hours before or approximately 2 hours after a single 400-mg nilotinib dose.

Nirogacestat: (Moderate) Separate the administration of nirogacestat and antacids by at least 2 hours. Simultaneous coadministration may impair nirogacestat absorption resulting in reduced exposure and efficacy.

Norethindrone Acetate; Ethinyl Estradiol; Ferrous fumarate: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.

Norethindrone; Ethinyl Estradiol; Ferrous fumarate: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.

Octreotide: (Moderate) Coadministration of oral octreotide with antacids may require increased doses of octreotide. Coadministration of oral octreotide with drugs that alter the pH of the upper GI tract, including antacids, may alter the absorption of octreotide and lead to a reduction in bioavailability.

Ofloxacin: (Moderate) Administer magnesium carbonate at least 2 hours before or 2 hours after ofloxacin. Ofloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. (Moderate) Administer oral products that contain magnesium at least 2 hours before or 2 hours after ofloxacin. Ofloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations.

Omadacycline: (Moderate) Administer oral magnesium-containing products at least 3 hours before or 3 hours after orally administered tetracyclines. Tetracycline absorption may be reduced as tetracycline antibiotics can chelate with divalent or trivalent cations. (Moderate) Separate administration of omadacycline and antacids by 4 hours. Coadministration may impair absorption of omadacycline which may decrease its efficacy.

Oxybutynin: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Pancrelipase: (Major) The effectiveness of gastrointestinal enzymes can be diminished with concurrent administration of antacids. In-vitro studies suggest that calcium and magnesum cations exert their deleterious effect on replacement enzyme therapy by formation of poorly soluble calcium or magnesium soaps and precipitation of glycine conjugated bile salts.

Pancuronium: (Moderate) Concomitant use of neuromuscular blockers and magnesium may prolong neuromuscular blockade. The use of a peripheral nerve stimulator is strongly recommended to evaluate the level of neuromuscular blockade, to assess the need for additional doses of neuromuscular blocker, and to determine whether adjustments need to be made to the dose with subsequent administration.

Paricalcitol: (Major) Avoid vitamin D analog coadministration with magnesium-containing products, such as antacids, in persons on chronic hemodialysis due to the risk for hypermagnesemia.

Pazopanib: (Moderate) Separate administration of pazopanib and antacids by several hours if coadministration is necessary in order to avoid a reduction in pazopanib exposure, which may decrease efficacy.

Penicillamine: (Moderate) Because penicillamine chelates heavy metals, it is possible that antacids could reduce penicillamine bioavailability, which can decrease the therapeutic effects of penicillamine. Simultaneous administration should be avoided; separate dosing by at least 2 hours to limit an interaction.

Perindopril: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Perindopril; Amlodipine: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Pexidartinib: (Moderate) Administer pexidartinib 2 hours before or after locally-acting antacids as concurrent administration may reduce pexidartinib exposure. Although the effects of locally-acting antacids on pexidartinib pharmacokinetics have not been studied, other acid-reducing agents have been shown to decrease pexidartinib exposure by 50%.

Phenobarbital; Hyoscyamine; Atropine; Scopolamine: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Phenytoin: (Moderate) Because the absorption of phenytoin suspension can be reduced by antacids containing magnesium, aluminum, or calcium, administration at the same time of day should be avoided when possible. Ingestion times of phenytoin capsules and calcium antacids should be staggered in patients with low serum phenytoin levels to prevent absorption difficulties. Studies evaluating the effects of magnesium-aluminium antacids on the absorption of phenytoin capsules or tablets have yielded conflicting results. Nevertheless, serum phenytoin levels and clinical response should be closely monitored if these agents are co-administered. The mechanisms by which antacids reduce phenytoin absorption may involve increased gastric transit time, chelation, adsorption, and/or altered solubility. The oral absorption of phenytoin may be reduced by calcium carbonate (e.g., as found in antacids) or other calcium salts. Calcium products may form complexes with phenytoin that are nonabsorbable. Although the magnitude of the interaction is not great, an occasional patient may be affected and the interaction may lead to subtherapeutic phenytoin concentrations. Separating the administration of phenytoin and antacids or calcium salts by at least 2 hours will help minimize the possibility of interaction.

Phosphorated Carbohydrate Solution: (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products.

Phosphorus: (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products.

Polycarbophil: (Moderate) Oral calcium-containing medications, such as calcium polycarbophil, may increase serum calcium or magnesium concentrations in susceptible patients, primarily in patients with renal insufficiency. Calcium and magnesium salts are often combined together in nutritional supplements and vitamin products. Each 625 mg of calcium polycarbophil contains a substantial amount of calcium (approximately 125 mg).

Polyethylene Glycol; Electrolytes; Bisacodyl: (Minor) The concomitant use of bisacodyl tablets with antacids can cause the enteric coating of the bisacody tablet to dissolve prematurely, leading to possible gastric irritation or dyspepsia. Avoid antacids within 1 hour before or after the bisacodyl dosage.

Polysaccharide-Iron Complex: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.

Potassium Citrate: (Contraindicated) Avoid coadministration of antacids with citrate salts since increased absorption of aluminum can occur. In addition, some antacids like calcium carbonate, share the potential with the citrate salts for development of metabolic alkalosis, when given in higher dosage.

Potassium Phosphate: (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products.

Potassium Phosphate; Sodium Phosphate: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products.

Propantheline: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Propranolol: (Moderate) Antacids may reduce the absorption of propranolol. The need to stagger doses of propranolol has not been established, but may be prudent. Monitor clinical response, and adjust propranolol dosage if needed to attain therapeutic goals.

Pyridostigmine: (Moderate) Magnesium salts may enhance the neuromuscular blockade and may interfere with the restoration of neuromuscular function. Consider the possibility of enhanced neuromuscular blockade from magnesium salts during pyridostigmine administration.

Quinapril: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Quinapril; Hydrochlorothiazide, HCTZ: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Quinidine: (Major) Alkalinizing agents such as antacids can increase renal tubular reabsorption of quinidine by alkalinizing the urine; higher quinidine serum concentrations and quinidine toxicity are possible.

Quinine: (Major) Antacids may delay or decrease the absorption of quinine.

Raltegravir: (Major) Coadministration or staggered administration of aluminum and/or magnesium-containing antacids is not recommended during treatment with raltegravir. Coadministration may result in decreased plasma concentrations of raltegravir, which may lead to HIV treatment failure or the development of viral resistance. In a drug interaction study, the AUC for raltegravir was decreased by 49% (90% CI, 35% to 60%), 51% (90% CI, 33% to 65%), and 30% (90% CI, 4% to 50%), when administered with, 2 hours before, and 2 hours after aluminum/magnesium hydroxide antacids, respectively.

Ramipril: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Rifampin: (Moderate) Concomitant use of antacids and rifampin may decrease the absorption of rifampin. Daily doses of rifampin should be given at least 1 hour before the ingestion of antacids.

Rilpivirine: (Moderate) Concurrent administration of rilpivirine and antacids may significantly decrease rilpivirine plasma concentrations, potentially resulting in treatment failure. To decrease the risk of virologic failure, avoid use of antacids for at least 2 hours before and at least 4 hours after administering rilpivirine.

Riociguat: (Major) Separate administration of riociguat from antacids by at least 1 hour. Antacids such as aluminum hydroxide/magnesium hydroxide decrease riociguat absorption.

Risedronate: (Moderate) Oral magnesium may significantly reduce the absorption of the oral bisphosphonates (e.g., risedronate). All medications should be administered at least 30 minutes after a risedronate dose to help prevent these absorption interactions. Some recommend that divalent cation-containing products should preferentially be taken at least 2 hours after oral bisphosphonates or at a completely different time of day.

Rocuronium: (Moderate) Concomitant use of neuromuscular blockers and magnesium may prolong neuromuscular blockade. The use of a peripheral nerve stimulator is strongly recommended to evaluate the level of neuromuscular blockade, to assess the need for additional doses of neuromuscular blocker, and to determine whether adjustments need to be made to the dose with subsequent administration.

Rosuvastatin: (Moderate) Coadministration of rosuvastatin with antacids has reduced rosuvastatin plasma concentrations by 54%. When the antacid is given 2 hours after rosuvastatin, no significant change in rosuvastatin plasma concentrations is observed.

Rosuvastatin; Ezetimibe: (Moderate) Coadministration of rosuvastatin with antacids has reduced rosuvastatin plasma concentrations by 54%. When the antacid is given 2 hours after rosuvastatin, no significant change in rosuvastatin plasma concentrations is observed. (Minor) Antacids may decrease the peak plasma concentration (Cmax) of total ezetimibe by 30%. The effect of the antacids in this regard is not expected to have a significant effect on the ability of ezetimibe to lower cholesterol. However, to limit any potential interaction, it would be prudent to administer ezetimibe at least 1 hour before or 2 hours after administering antacids.

Sarecycline: (Major) Separate administration of sarecycline and antacids by 2 to 3 hours. Coadministration may impair absorption of sarecycline which may decrease its efficacy. (Moderate) Administer oral magnesium-containing products at least 3 hours before or 3 hours after orally administered tetracyclines. Tetracycline absorption may be reduced as tetracycline antibiotics can chelate with divalent or trivalent cations.

Scopolamine: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Selpercatinib: (Major) Avoid coadministration of selpercatinib with antacids due to the risk of decreased selpercatinib exposure which may reduce its efficacy. If concomitant use is unavoidable, take selpercatinib 2 hours before or 2 hours after administration of antacids. Coadministration with acid-reducing agents decreases selpercatinib plasma concentrations.

Sodium Benzoate; Sodium Phenylacetate: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers.

Sodium Citrate; Citric Acid: (Contraindicated) Avoid coadministration of antacids with citrate salts since increased absorption of aluminum can occur. In addition, some antacids like calcium carbonate, share the potential with the citrate salts for development of metabolic alkalosis, when given in higher dosage.

Sodium Ferric Gluconate Complex; ferric pyrophosphate citrate: (Moderate) Doses of antacids and iron should be taken as far apart as possible to minimize the potential for interaction. Antacids may decrease the absorption of oral iron preparations. At higher pH values, iron is more readily ionized to its ferric state and is more poorly absorbed.

Sodium Fluoride: (Major) Absorption of sodium fluoride may be reduced by concomitant use of magnesium supplements or antacids that contain magnesium. An interval of at least 2 hours is advisable between administration of sodium fluoride and magnesium salts.

Sodium Phosphate Monobasic Monohydrate; Sodium Phosphate Dibasic Anhydrous: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers.

Sodium Polystyrene Sulfonate: (Major) Simultaneous oral administration of cation-donating antacids or laxatives may reduce the potassium exchange capability of sodium polystyrene sulfonate. Examples of cation-donating antacids and laxatives include aluminum hydroxide, calcium carbonate, magnesium carbonate, magnesium citrate, and magnesium hydroxide. Patients who received concomitant oral sodium polystyrene sulfonate and non-absorbable cation-donating antacids and laxatives have developed systemic alkalosis. Intestinal obstruction due to concretions of aluminum hydroxide when used in combination with sodium polystyrene sulfonate has also been reported. One case of grand mal seizure has been reported in a patient with chronic hypocalcemia of renal failure who was given sodium polystyrene with magnesium hydroxide as laxative. Normally, antacids like magnesium hydroxide and calcium carbonate neutralize hydrochloric acid in the stomach, forming magnesium chloride and calcium chloride. As these compounds enter the small intestine, they react with bicarbonate, forming magnesium carbonate and calcium carbonate, which are insoluble. If polystyrene is administered, it blocks this reaction by binding to the magnesium and calcium ions before they can react with the bicarbonate. More hydrogen ions are lost from the stomach than are lost from the intestine, resulting in metabolic alkalosis. Rectal administration of sodium polystyrene sulfonate may reduce the severity of these interactions.

Sofosbuvir; Velpatasvir: (Moderate) Separate the use of antacids and velpatasvir administration by 4 hours. Velpatasvir solubility decreases as pH increases; therefore, drugs that increase gastric pH are expected to decrease the concentrations of velpatasvir, potentially resulting in loss of antiviral efficacy.

Sofosbuvir; Velpatasvir; Voxilaprevir: (Moderate) Separate the use of antacids and velpatasvir administration by 4 hours. Velpatasvir solubility decreases as pH increases; therefore, drugs that increase gastric pH are expected to decrease the concentrations of velpatasvir, potentially resulting in loss of antiviral efficacy.

Sotalol: (Moderate) Coadministration of antacids with sotalol reduces the Cmax and AUC of sotalol by 26% and 20%, respectively. This interaction results in a 25% reduction in the bradycardic effect of sotalol (measured at rest). Antacid administration two hours after the sotalol dose does not alter sotalol pharmacokinetics or pharmacodynamics. Instruct patients to avoid using antacids containing aluminum hydroxide or magnesium hydroxide within 2 hours of taking sotalol.

Sotorasib: (Moderate) Avoid coadministration of sotorasib and gastric-reducing agents, such as antacids. Coadministration may decrease sotorasib exposure resulting in decreased efficacy. If coadministration with antacids is necessary, administer sotorasib 4 hours before or 10 hours after an antacid.

Sparsentan: (Moderate) Administer sparsentan 2 hours before or after antacids. Simultaneous coadministration may decrease sparsentan exposure and efficacy. Medications that affect gastric pH may reduce sparsentan absorption.

Succinylcholine: (Moderate) Concomitant use of neuromuscular blockers and magnesium may prolong neuromuscular blockade. The use of a peripheral nerve stimulator is strongly recommended to evaluate the level of neuromuscular blockade, to assess the need for additional doses of neuromuscular blocker, and to determine whether adjustments need to be made to the dose with subsequent administration.

Sucralfate: (Moderate) Antacids can interfere with the binding capacity of sucralfate to the GI mucosa, decreasing its effectiveness. Antacids should not be administered within 30 minutes of sucralfate. In addition, antacids or other aluminum-containing agents should be used cautiously with sucralfate in patients with chronic renal failure due to the aluminum content of sucralfate and the potential for aluminum toxicity.

Sulfacetamide; Sulfur: (Major) Administration of oral magnesium with edetate disodium, disodium EDTA may result in binding of magnesium. Do not administer oral magnesium salts within 1 hour of edetate disodium, EDTA.

Sumatriptan; Naproxen: (Minor) Concomitant administration of antacids can delay the absorption of naproxen. Periodic antacid use should not be problematic as long as the antacid and enteric-coated naproxen administration are separated by at least 2 hours.

Tetracycline: (Moderate) Administer oral magnesium-containing products at least 3 hours before or 3 hours after orally administered tetracyclines. Tetracycline absorption may be reduced as tetracycline antibiotics can chelate with divalent or trivalent cations. (Moderate) Separate administration of tetracycline and antacids by 2 to 3 hours. Coadministration may impair absorption of tetracycline which may decrease its efficacy.

Tetracyclines: (Moderate) Administer oral magnesium-containing products at least 3 hours before or 3 hours after orally administered tetracyclines. Tetracycline absorption may be reduced as tetracycline antibiotics can chelate with divalent or trivalent cations.

Thyroid hormones: (Moderate) Administer thyroid hormones at least 4 hours before or after antacids, dietary supplements, or other drugs containing magnesium. Magnesium salts have been reported to chelate oral thyroid hormones within the GI tract when administered simultaneously, leading to decreased thyroid hormone absorption. Some case reports have described clinical hypothyroidism resulting from coadministration of levothyroxine with products containing oral cations, such as antacids or dietary supplements.

Tipranavir: (Moderate) Concurrent administration of tipranavir and ritonavir with antacids results in decreased tipranavir concentrations. Administer tipranavir and ritonavir 2 hours before or 1 hour after antacids.

Tramadol; Acetaminophen: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.

Trandolapril: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Trandolapril; Verapamil: (Moderate) Use caution when prescribing sulfate salt bowel preparation in patients taking concomitant medications that may affect renal function such as angiotensin-converting enzyme inhibitors (ACE inhibitors).

Trientine: (Major) In general, oral mineral supplements should not be given since they may block the oral absorption of trientine. However, iron deficiency may develop, especially in children and menstruating or pregnant women, or as a result of the low copper diet recommended for Wilson's disease. If necessary, iron may be given in short courses, but since iron and trientine each inhibit oral absorption of the other, 2 hours should elapse between administration of trientine and iron doses.

Trihexyphenidyl: (Moderate) Antacids may inhibit the oral absorption of anticholinergics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Trospium: (Moderate) Antacids may inhibit the oral absorption of antimuscarinics. Simultaneous oral administration should be avoided when feasible; separate dosing by at least 2 hours to limit an interaction.

Vecuronium: (Moderate) Concomitant use of neuromuscular blockers and magnesium may prolong neuromuscular blockade. The use of a peripheral nerve stimulator is strongly recommended to evaluate the level of neuromuscular blockade, to assess the need for additional doses of neuromuscular blocker, and to determine whether adjustments need to be made to the dose with subsequent administration.

Vincristine Liposomal: (Major) Antacids may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers.

Vitamin D analogs: (Major) Avoid vitamin D analog coadministration with magnesium-containing products, such as antacids, in persons on chronic hemodialysis due to the risk for hypermagnesemia.

Vitamin D: (Major) Avoid vitamin D coadministration with magnesium-containing products, such as antacids, in persons on chronic hemodialysis due to the risk for hypermagnesemia.

Vitamin D: (Major) Avoid vitamin D coadministration with magnesium-containing products, such as antacids, in persons on chronic hemodialysis due to the risk for hypermagnesemia.

Magnesium is a cofactor to all enzymes involved in phosphate transfer reactions that use ATP and other nucleotides as substrates. Magnesium ions are a cofactor for the normal function of the ATP-dependent sodium-potassium "pump" found in muscle membranes. Without magnesium, the efficiency of this pump is compromised. It is believed that hypomagnesemia is an important aspect of hypokalemia. Drugs that cause severe hypokalemia, such as cisplatin, amphotericin B, and loop diuretics, also cause hypomagnesemia. Correction of hypomagnesemia facilitates the treatment of hypokalemia by improving the pump's ability to distribute potassium into the intracellular space. This mechanism also may explain the effectiveness of intravenous magnesium sulfate in treating cardiac glycoside-induced arrhythmias, although magnesium may exert therapeutic effects independently of a direct action on the sodium-potassium pump. It is postulated that magnesium is effective via its ability to decrease calcium uptake and decrease potassium efflux at the myocardial cell membrane. Conversely, calcium is a direct antagonist of magnesium.

Magnesium is also necessary for binding of intracellular macromolecules to organelles and mRNA to ribosomes. As a laxative, magnesium sulfate exerts its action primarily in the small intestine. The accepted mechanisms include a hyperosmotic effect from magnesium in the small intestine and stimulation of stretch receptors and peristalsis through retention of water. Other evidence indicates, however, that hyperosmolarity does not occur and that cholecystokinin release or decreased transit time are potential contributory mechanisms.

The mechanism of the antacid effects of magnesium oxide involves reaction with water. In the presence of water, magnesium oxide is converted to magnesium hydroxide which rapidly reacts with gastric acid to form water and magnesium chloride, thereby increasing gastric pH.

The role of magnesium for the treatment of severe asthma exacerbations is not clearly defined. Magnesium decreases the uptake of calcium by bronchial smooth muscle cells, which results in bronchodilation. Magnesium may also inhibit mast cell degranulation, thus decreasing inflammatory mediators such as histamine, thromboxanes, and leukotrienes. Additionally, magnesium inhibits the release of acetylcholine from motor nerve terminals and depresses the excitability of muscle fiber membranes. Magnesium also stimulates nitric oxide and prostacyclin synthesis, which may decrease asthma severity.

High magnesium serum concentrations result in vasodilation, muscle relaxation, and sedation. Some studies have shown that magnesium can prevent and reduce hypoxia-induced pulmonary hypertension, leading to its use in the treatment of persistent pulmonary hypertension of the newborn (PPHN).

As an anticonvulsant, magnesium sulfate depresses the CNS and blocks peripheral neuromuscular transmission. Depression in the CNS may be achieved through inhibition of acetylcholine release by motor nerve impulses. Magnesium is a peripheral vasodilator and an inhibitor of platelet function. Large doses can lower blood pressure and cause CNS depression.

Magnesium sulfate is administered orally or parenterally; magnesium chloride, gluconate, lactate, and oxide are administered orally. Magnesium is distributed throughout the body. Approximately one-half of the total magnesium in the body is present in soft tissue; most of the remaining magnesium is present in bone. Less than 1% of the total body magnesium is present the blood. Normal serum concentrations range 1.4 to 2 mEq/L in adults, 1.5 to 2 mEq/L in children, and 1.5 to 2.3 mEq/L in neonates and infants. As an anticonvulsant, effective serum magnesium concentrations have been reported to range from 2.5 to 7.5 mEq/L. Magnesium crosses the placenta and is excreted into breast milk; however, problems in humans have not been documented. Magnesium is not metabolized. Elimination occurs renally, but the rate of excretion varies. Approximately 1.5 g (12 mEq) of magnesium is excreted in the urine daily. Magnesium ions are reabsorbed in the thick ascending limb of the loop of Henle.


-Route-Specific Pharmacokinetics
Oral Route
Approximately 34 to 40% of oral magnesium salts are absorbed systemically with a normal diet; however, absorption can increase to 76% in those receiving only 2 mEq/day of magnesium.

Intravenous Route
Intravenous administration of magnesium sulfate produces an immediate effect that lasts for about 30 minutes.

Intramuscular Route
Following IM administration of magnesium sulfate, the onset of action occurs in 1 hour and the duration of action is about 4 hours.