Cefdinir (FK482, CI-983) is an oral extended-spectrum, semisynthetic, cephalosporin. It is generally classified as a third generation cephalosporin with activity similar to cefotaxime and cefixime. In a comparison to cefixime, cefpodoxime, cefaclor, and cephalexin in vitro, cefdinir is more active against oxacillin-sensitive Staphylcoccus aureus and coagulase-negative staphylococci, Streptococcus pneumoniae, S. pyogens, Escherichia coli, and Moraxella catarrhalis. Cefdinir is less active than cefixime against Hemophilus influenzae, Klebsiella pneumonia, K. oxytoca, Proteus mirabilis and P. vulgaris. Cefdinir is not active against methicillin-resistant staphylococci or Pseudomonas aeruginosa. A post-antibiotic effect of cefdinir has been shown against S. aureus and S. pyogens but not against E. coli or K. pneumonia. Cefdinir is approved for treatment of skin infections and a variety of upper respiratory infections including chronic bronchitis, otitis media, pharyngitis, pneumonia, sinusitis, and tonsillitis in both adult and pediatric patients. It is available in both capsules and in a strawberry-flavored suspension. Final FDA approval was granted December 8, 1997.
General Administration Information
For storage information, see the specific product information within the How Supplied section.
Route-Specific Administration
Oral Administration
-If antacids or iron supplements are necessary during cefdinir therapy, cefdinir should be given at least 2 hours before or after the antacid or iron supplement. Iron-fortified infant formulas do not significantly alter the absorption of cefdinir.
Oral Solid Formulations
-Cefdinir capsules may be administered without regard to meals.
Oral Liquid Formulations
-Cefdinir oral suspension may be administered without regard to meals.
-Shake well prior to each use.
-For accurate dosage, measure using a calibrated oral syringe, spoon or cup.
Suspension Reconstitution:
-Tap the bottle to loosen the powder. The water will be added in 2 portions; shake well after each aliquot.
-See manufacturer's specific instructions regarding reconstitution volumes needed. Each manufacturer will have different instructions regarding the amount of water needed to obtain either the 125 mg/5 mL or 250 mg/mL concentrations.
-After mixing, the suspension can be stored at controlled room temperature. The container should be kept tightly closed when not in use. Shake well prior to each use. The suspension may be used for 10 days, after which any unused portion must be discarded.
In clinical trials, 5093 adult and adolescent patients (3841 US and 1252 non-US) were treated with the recommended dose of cefdinir capsules (600 mg/day) and 2289 pediatric patients (1783 US and 506 non-US) were treated with the recommended dose of cefdinir suspension (14 mg/kg/day). Most adverse events were mild and self-limiting. No deaths or permanent disabilities were attributed to cefdinir. One hundred forty-seven (3%) adult/adolescent patients and 40 (2%) pediatric patients discontinued medication due to adverse events thought by the investigators to be possibly, probably, or definitely associated with cefdinir therapy. The discontinuations were primarily for gastrointestinal disturbances. Nineteen (0.4%) adult/adolescent patients and five (0.2%) pediatric patients were discontinued due to rash thought related to cefdinir administration.
Hypersensitivity or allergic reactions have occurred in patients receiving beta-lactam antibiotics, including cefdinir. Rash (unspecified) has been reported in 0.9% of adults and adolescents and in 3% of pediatric patients. Rash (primarily diaper rash) was reported in 8% of patients <= 2 years old and in 1% of pediatric patients > 2 years old. Pruritus has been reported in 0.2% of patients. Other reactions noted in post-marketing reports include anaphylactoid reactions and anaphylactic shock with rare cases of fatality, facial edema (angioedema), laryngeal edema, erythema multiforme, erythema nodosum, exfoliative dermatitis, maculopapular rash, serum sickness, Stevens-Johnson syndrome, toxic epidermal necrolysis, and allergic vasculitis. If an allergic reaction occurs, cefdinir therapy should be discontinued and appropriate therapy instigated.
In clinical trials, gastrointestinal disturbances were the most commonly reported reasons for cefdinir discontinuation. Diarrhea was reported in 8% of pediatric patients and in 15% of adults and adolescents. In pediatric patients <= 2 years old, the incidence of diarrhea was 17% compared to 4% in patients > 2 years old. Other adverse events included nausea (0.2-3%), abdominal pain (0.8-1%), vomiting (0.7-1%), dyspepsia (0.2-0.7%), abnormal stools (0.2-3%), anorexia (0.3%), flatulence (0.7%), constipation (0.3%), and xerostomia (0.3%). Acute enterocolitis, bloody diarrhea, hemorrhagic colitis, melena, peptic ulcer, stomatitis, and ileus have been noted in post-marketing reports.
Microbial overgrowth and superinfection can occur with antibiotic use. C. difficile-associated diarrhea (CDAD) or pseudomembranous colitis has been reported with cefdinir. If pseudomembranous colitis is suspected or confirmed, ongoing antibacterial therapy not directed against C. difficile may need to be discontinued. Institute appropriate fluid and electrolyte management, protein supplementation, C. difficile-directed antibacterial therapy, and surgical evaluation as clinically appropriate. Candidiasis (unspecified) has been reported in 0.2% of patients. Cutaneous candidiasis has been reported in 0.9% of pediatric patients while vaginal candidiasis has been noted in 0.3% of pediatric patients and in 4% of adults. Vaginitis was reported in 0.3% of pediatric patients and in 1% of adults.
Several case reports describe nonbloody, reddish stool discoloration reported in infants being treated with cefdinir who were also receiving iron-fortified infant formulas. There have been reports of reddish stools in patients of all ages receiving cefdinir. In many cases, patients were also receiving iron-containing products. The reddish color is due to the formation of a nonabsorbable complex between cefdinir or its breakdown products and iron in the gastrointestinal tract. The stool discoloration is not harmful.
Seizures are a rare but serious complication of cephalosporin therapy. Seizures have been reported in < 1% of patients receiving cephalosporins. More commonly associated with penicillins, the epileptogenic properties of both penicillins and cephalosporins are believed to be related to their beta-lactam ring. High doses and renal impairment are associated with an increased risk of seizures. Post-marketing reports have included cases of seizures during cefdinir therapy. Headache was reported in 2% of patients receiving cefdinir. Dizziness (0.3%), insomnia (0.2%), and somnolence/drowsiness (0.2%) have also been reported. Loss of consciousness was noted in post-marketing reports.
Hematologic adverse events have been noted with the use of cefdinir. Increased lymphocytes have been reported in <= 2% of cefdinir patients. Adverse events reported in <= 1% of patients include increased and decreased white blood cells, eosinophilia, decreased lymphocytes, increased platelets, increased or decreased PMNs, increased monocytes, decreased hematocrit, and decreased hemoglobin. Post-marketing adverse events and include pancytopenia, granulocytopenia, leukopenia, thrombocytopenia, idiopathic thrombotic thrombocytopenic purpura (TTP), hemolytic anemia, bleeding tendency, coagulation disorders, disseminated intravascular coagulation (DIC), and upper GI bleeding. Aplastic anemia, neutropenia, and agranulocytosis have been noted with the cephalosporin class.
Elevated hepatic enzymes (AST, ALT, alkaline phosphatase, GGT) and hyperbilirubinemia were noted in <= 1% of patients receiving cefdinir. Hepatic adverse events noted in post-marketing reports include acute hepatitis, cholestasis, fulminant hepatitis, hepatic failure, and jaundice.
Hyperkinesis (0.2%) and asthenia (0.2%) have both been reported with cefdinir use. Other adverse events noted in post-marketing reports include involuntary movements and rhabdomyolysis.
Genitourinary adverse events have been reported with the use of cefdinir. Leukorrhea was noted in 0.2% of women. Abnormal urinary laboratory values including increased urine leukocytes (0.5-2%), increased micro-hematuria (1%), and increased urine protein/proteinuria (1-2%) have been reported. Other abnormal laboratory values that occurred in < 1% of patients include increased urine glucose/glycosuria, increased or decreased urine specific gravity, increased urine pH, and increased BUN/azotemia. Acute renal failure (unspecified) and nephropathy were noted in post-marketing reports.
Abnormal laboratory values that have been reported in <= 1% of patients with the use of cefdinir include elevated bicarbonate, elevated lactate dehydrogenase, hyperphosphatemia, hypophosphatemia, hypocalcemia, hyperglycemia, and hyperkalemia. Hyperamylasemia has been noted in post-marketing reports.
General adverse events noted in post-marketing reports with cefdinir include a feeling of suffocation, conjunctivitis, and fever.
Respiratory system adverse events noted in post-marketing reports with cefdinir include acute respiratory failure (respiratory arrest), asthmatic attack, drug-induced pneumonia, eosinophilic pneumonia, and idiopathic interstitial pneumonia.
Cardiovascular adverse events noted in post-marketing reports with cefdinir include heart failure, chest pain (unspecified), myocardial infarction, and hypertension.
A false-positive reaction for glucose in the urine has been observed in patients receiving cephalosporins, such as cefdinir, and using Benedict's solution, Fehling's solution, or Clinitest tablets for urine glucose testing. However, this reaction has not been observed with glucose oxidase tests (e.g., Tes-tape, Clinistix, Diastix). Patients with diabetes mellitus who test their urine for glucose should use glucose tests based on enzymatic glucose oxidase reactions while on cefdinir treatment.
A positive direct Coombs test may develop in some patients. In hematologic studies or in transfusion cross-matching procedures when antiglobulin tests are performed on the minor side or in Coombs test of newborns whose mothers received cefdinir before delivery, clinicians should keep in mind that a positive Coombs test may be due to the drug.
Cefdinir does not treat viral infection (e.g., common cold). Prescribing in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria (antimicrobial resistance). Patients should be told to complete the full course of treatment, even if they feel better earlier.
Cefdinir is contraindicated in patients with a known history of cephalosporin hypersensitivity or cephamycin hypersensitivity. Cefdinir should be used cautiously in patients with hypersensitivity to penicillin. The structural similarity between cefdinir and penicillin means cross-reactivity can occur. Penicillins can cause a variety of hypersensitivity reactions ranging from mild rash to fatal anaphylaxis. Patients who have experienced severe penicillin hypersensitivity should not receive cefdinir. The incidence of cephalosporin hypersensitivity is approximately 3-7% among patients with a documented history of penicillin hypersensitivity. Cefdinir should be used with caution in patients who have had a delayed-type reaction to penicillin or related drugs. Serum sickness-like reactions have occurred following a second course of therapy.
In patients with transient or persistent renal impairment (creatinine clearance <30 mL/min) or renal failure, the total daily dose of cefdinir should be reduced because high and prolonged plasma concentrations of cefdinir can result following recommended doses. Because hemodialysis removes cefdinir from the body, additional dosage adjustments are needed to ensure therapeutic effect if a patient receives dialysis.
Consider pseudomembranous colitis in patients presenting with diarrhea after antibacterial use. Careful medical history is necessary as pseudomembranous colitis has been reported to occur over 2 months after the administration of antibacterial agents. Almost all antibacterial agents, including cefdinir, have been associated with pseudomembranous colitis or C. difficile-associated diarrhea (CDAD) which may range in severity from mild to life-threatening. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile.
All cephalosporins, including cefdinir, can rarely cause hypoprothrombinemia and have the potential to cause bleeding. Cephalosporins, which contain the methylthiotetrazole (MTT) side chain (e.g., cefoperazone, cefamandole, cefotetan), have been associated with an increased risk for bleeding. Cephalosporins should be used cautiously in patients with a preexisting coagulopathy (e.g., vitamin K deficiency) because these patients are at a higher risk for developing bleeding complications.
In patients with diabetes mellitus, it should be noted that cefdinir oral suspension contains sucrose (1.37 to 2.94 g per teaspoon depending on manufacturer), which may be a concern in patients whose blood glucose is very sensitive to carbohydrate intake.
Safety and efficacy of cefdinir in neonates and infants less than 6 months of age have not been established.
Cefdinir is classified in FDA pregnancy risk category B. Animal data show that there are no teratogenic effects of cefdinir in rats. There are, however, no adequate and well-controlled studies in pregnant women, Because animal reproduction studies are not always predictive of human response, cefdinir should be used during pregnancy only if clearly needed.
Cefdinir may be administered to breast-feeding women. Cefdinir was not detected in human breast milk following single 600-mg oral doses.
Dose adjustment of cefdinir is not necessary in the geriatric patient unless renal function is markedly compromised. Clinical trial data and clinical experience suggests similar efficacy toin geriatric and younger adult patients. The federal Omnibus Budget Reconciliation Act (OBRA) regulates medication use in residents (geriatric adults) of long-term care facilities. According to OBRA, use of antibiotics should be limited to confirmed or suspected bacterial infections. Antibiotics are non-selective and may result in the eradication of beneficial microorganisms while promoting the emergence of undesired ones, causing secondary infections such as oral thrush, colitis, or vaginitis. Any antibiotic may cause diarrhea, nausea, vomiting, anorexia, and hypersensitivity reactions.
To reduce the development of drug-resistant bacteria and maintain the effectiveness of antibacterial drugs, this drug should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
Per the manufacturer, this drug has been shown to be active against most strains of the following microorganisms either in vitro and/or in clinical infections: Citrobacter koseri, Escherichia coli, Haemophilus influenzae (beta-lactamase negative), Haemophilus influenzae (beta-lactamase positive), Haemophilus parainfluenzae, Klebsiella pneumoniae, Moraxella catarrhalis, Proteus mirabilis, Staphylococcus aureus (MSSA), Staphylococcus epidermidis, Streptococcus agalactiae (group B streptococci), Streptococcus pneumoniae, Streptococcus pyogenes (group A beta-hemolytic streptococci), Viridans streptococci
NOTE: The safety and effectiveness in treating clinical infections due to organisms with in vitro data only have not been established in adequate and well-controlled clinical trials.
For the treatment of acute otitis media:
Oral dosage:
Children 6 years and older: 7 mg/kg/dose (Max: 300 mg/dose) PO every 12 hours or 14 mg/kg/dose (Max: 600 mg/dose) PO every 24 hours for 5 to 7 days for mild to moderate disease and 10 days for severe disease. Guidelines recommend cefdinir as an alternative to high-dose amoxicillin or high-dose amoxicillin; clavulanate in penicillin allergic patients.
Children 2 to 5 years: 7 mg/kg/dose (Max: 300 mg/dose) PO every 12 hours or 14 mg/kg/dose (Max: 600 mg/dose) PO every 24 hours for 7 days for mild to moderate disease and 10 days for severe disease. Guidelines recommend cefdinir as an alternative to high-dose amoxicillin or high-dose amoxicillin; clavulanate in penicillin allergic patients.
Infants and Children 6 to 23 months: 7 mg/kg/dose (Max: 300 mg/dose) PO every 12 hours or 14 mg/kg/dose (Max: 600 mg/dose) PO every 24 hours for 10 days. Guidelines recommend cefdinir as an alternative to high-dose amoxicillin or high-dose amoxicillin; clavulanate in penicillin allergic patients.
Infants 2 to 5 months*: 7 mg/kg/dose PO every 12 hours or 14 mg/kg/dose PO every 24 hours for 10 days. Guidelines recommend cefdinir as an alternative to high-dose amoxicillin or high-dose amoxicillin; clavulanate in penicillin allergic patients.
For the treatment of acute bacterial exacerbations of chronic bronchitis:
Oral dosage (capsules):
Adults: 300 mg PO every 12 hours or 600 mg PO every 24 hours for 5 to 7 days. The FDA-approved dosage is 300 mg PO every 12 hours for 5 to 10 days or 600 mg PO every 24 hours for 10 days.
Adolescents: 300 mg PO every 12 hours for 5 to 10 days or 600 mg PO every 24 hours for 10 days.
For the treatment of acute maxillary sinusitis:
Oral dosage:
Adults and Adolescents: 300 mg PO every 12 hours or 600 mg PO every 24 hours for 10 days. Third-generation oral cephalosporins, such as cefdinir, are not recommended by the Infectious Disease Society of America (IDSA) for empiric monotherapy of acute bacterial sinusitis due to variable rates of S. pneumoniae resistance.
Infants >= 6 months and Children: 7 mg/kg/dose PO every 12 hours (Max: 300 mg/dose) or 14 mg/kg/dose PO every 24 hours (Max: 600 mg/dose) for 10 days is recommended by the manufacturer. Third-generation oral cephalosporins, such as cefdinir, are not recommended by the Infectious Disease Society of America (IDSA) for empiric monotherapy of acute bacterial sinusitis due to variable rates of S. pneumoniae resistance.
For the treatment of community-acquired pneumonia (CAP):
Oral dosage:
Adults: 300 mg PO every 12 hours for 10 days.
Adolescents: 300 mg PO every 12 hours for 10 days. Guidelines recommend cefdinir as an alternative to amoxicillin or amoxicillin; clavulanate for infections due to H. influenzae.
Infants and Children 4 months to 12 years*: 7 mg/kg/dose (Max: 300 mg/dose) PO every 12 hours for 10 days. Guidelines recommend cefdinir as an alternative to amoxicillin or amoxicillin; clavulanate for infections due to H. influenzae.
For the treatment of pharyngitis or tonsillitis:
Oral dosage:
Adults: 300 mg PO every 12 hours for 5 to 10 days or 600 mg PO every 24 hours for 10 days. Guidelines do not recommend cefdinir for Group A Streptococcal pharyngitis to prevent rheumatic fever.
Adolescents: 300 mg PO every 12 hours for 5 to 10 days or 600 mg PO every 24 hours for 10 days. Guidelines do not recommend cefdinir for Group A Streptococcal pharyngitis to prevent rheumatic fever.
Infants 6 months and older and Children: 7 mg/kg/dose PO every 12 hours (Max: 300 mg/dose) for 5 to 10 days or 14 mg/kg/dose PO every 24 hours (Max: 600 mg/dose) for 10 days. Guidelines do not recommend cefdinir Group A Streptococcal pharyngitis to prevent rheumatic fever.
For the treatment of uncomplicated skin and skin structure infections:
Oral dosage (capsules):
Adults and Adolescents: 300 mg PO every 12 hours for 10 days.
Oral dosage (oral suspension):
Infants and Children 6 months and older: 7 mg/kg/dose PO every 12 hours (Max: 300 mg/dose) for 10 days.
For the treatment of acute uncomplicated cystitis* [urinary tract infection (UTI)*]:
Oral dosage:
Adults: 300 mg PO every 12 hours for 3 to 7 days.
Maximum Dosage Limits:
-Adults
600 mg/day PO.
-Geriatric
600 mg/day PO.
-Adolescents
600 mg/day PO.
-Children
14 mg/kg/day PO (Max: 600 mg/day).
-Infants
6 months and older: 14 mg/kg/day PO.
1 to 5 months: Safety and efficacy have not been established; however, 14 mg/kg/day PO has been used off-label.
-Neonates
Safety and efficacy have not been established.
Patients with Hepatic Impairment Dosing
Dosage adjustment is not necessary.
Patients with Renal Impairment Dosing
CrCl >=30 mL/min: No dosage adjustment needed.
CrCl < 30 mL/min: For adults, the dose of cefdinir should be 300 mg PO once daily. For pediatric patients, if the CrCl < 30 mL/min/1.73 m2, the dose should be 7 mg/kg (up to 300 mg) PO once daily.
Intermittent hemodialysis
Hemodialysis removes cefdinir from the body. In patients maintained on chronic hemodialysis, the recommended initial dosage regimen is a 300 mg (adults) or 7 mg/kg (pediatrics) PO every other day. At the conclusion of each hemodialysis session, 300 mg (or 7 mg/kg) should be given. Subsequent doses (300 mg or 7 mg/kg) are then administered every other day.
*non-FDA-approved indication
Aluminum Hydroxide: (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.
Aluminum Hydroxide; Magnesium Carbonate: (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.
Aluminum Hydroxide; Magnesium Hydroxide: (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.
Aluminum Hydroxide; Magnesium Hydroxide; Simethicone: (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.
Aluminum Hydroxide; Magnesium Trisilicate: (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.
Antacids: (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.
Bumetanide: (Minor) Nephrotoxicity associated with cephalosporins may be potentiated by concomitant therapy with loop diuretics. Clinicians should be aware that this may occur even in patients with minor or transient renal impairment.
Choline Salicylate; Magnesium Salicylate: (Moderate) Administer cefdinir at least 2 hours before or 2 hours after magnesium salicylate. Cefdinir absorption may be reduced.
Desogestrel; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Dienogest; Estradiol valerate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Drospirenone: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Drospirenone; Estetrol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Drospirenone; Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Drospirenone; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Drospirenone; Ethinyl Estradiol; Levomefolate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Elagolix; Estradiol; Norethindrone acetate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Estradiol; Levonorgestrel: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Estradiol; Norethindrone: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Estradiol; Norgestimate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Ethacrynic Acid: (Minor) Nephrotoxicity associated with cephalosporins may be potentiated by concomitant therapy with loop diuretics. Clinicians should be aware that this may occur even in patients with minor or transient renal impairment.
Ethinyl Estradiol; Norelgestromin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Ethinyl Estradiol; Norethindrone Acetate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Ethinyl Estradiol; Norgestrel: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Ethynodiol Diacetate; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Etonogestrel; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Ferric Maltol: (Moderate) Administer cefdinir at least 2 hours before or 2 hours after iron supplements. Cefdinir absorption may be reduced. Coadministration of cefdinir with a therapeutic iron supplement containing 60 mg of elemental iron or vitamins supplemented with 10 mg of elemental iron reduced extent of absorption by 80% and 31%, respectively.
Furosemide: (Minor) Nephrotoxicity associated with cephalosporins may be potentiated by concomitant therapy with loop diuretics. Clinicians should be aware that this may occur even in patients with minor or transient renal impairment.
Iron Salts: (Moderate) Administer cefdinir at least 2 hours before or 2 hours after iron supplements. Cefdinir absorption may be reduced. Coadministration of cefdinir with a therapeutic iron supplement containing 60 mg of elemental iron or vitamins supplemented with 10 mg of elemental iron reduced extent of absorption by 80% and 31%, respectively.
Iron: (Moderate) Administer cefdinir at least 2 hours before or 2 hours after iron supplements. Cefdinir absorption may be reduced. Coadministration of cefdinir with a therapeutic iron supplement containing 60 mg of elemental iron or vitamins supplemented with 10 mg of elemental iron reduced extent of absorption by 80% and 31%, respectively.
Lanthanum Carbonate: (Moderate) To limit absorption problems, cefdinir should not be taken within 2 hours of dosing with lanthanum carbonate. Oral drugs known to interact with cationic antacids, like cefdinir, may be bound by lanthanum carbonate. Separate the times of administration appropriately. Monitor the patient to ensure the appropriate response to cefdinir is obtained.
Leuprolide; Norethindrone: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Levonorgestrel: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Levonorgestrel; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Levonorgestrel; Ethinyl Estradiol; Ferrous Bisglycinate: (Moderate) Administer cefdinir at least 2 hours before or 2 hours after iron supplements. Cefdinir absorption may be reduced. Coadministration of cefdinir with a therapeutic iron supplement containing 60 mg of elemental iron or vitamins supplemented with 10 mg of elemental iron reduced extent of absorption by 80% and 31%, respectively. (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Levonorgestrel; Ethinyl Estradiol; Ferrous Fumarate: (Moderate) Administer cefdinir at least 2 hours before or 2 hours after iron supplements. Cefdinir absorption may be reduced. Coadministration of cefdinir with a therapeutic iron supplement containing 60 mg of elemental iron or vitamins supplemented with 10 mg of elemental iron reduced extent of absorption by 80% and 31%, respectively. (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Loop diuretics: (Minor) Nephrotoxicity associated with cephalosporins may be potentiated by concomitant therapy with loop diuretics. Clinicians should be aware that this may occur even in patients with minor or transient renal impairment.
Magnesium Hydroxide: (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.
Magnesium Salicylate: (Moderate) Administer cefdinir at least 2 hours before or 2 hours after magnesium salicylate. Cefdinir absorption may be reduced.
Magnesium Salts: (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.
Norethindrone Acetate; Ethinyl Estradiol; Ferrous fumarate: (Moderate) Administer cefdinir at least 2 hours before or 2 hours after iron supplements. Cefdinir absorption may be reduced. Coadministration of cefdinir with a therapeutic iron supplement containing 60 mg of elemental iron or vitamins supplemented with 10 mg of elemental iron reduced extent of absorption by 80% and 31%, respectively. (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Norethindrone: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Norethindrone; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Norethindrone; Ethinyl Estradiol; Ferrous fumarate: (Moderate) Administer cefdinir at least 2 hours before or 2 hours after iron supplements. Cefdinir absorption may be reduced. Coadministration of cefdinir with a therapeutic iron supplement containing 60 mg of elemental iron or vitamins supplemented with 10 mg of elemental iron reduced extent of absorption by 80% and 31%, respectively. (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Norgestimate; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Norgestrel: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Oral Contraceptives: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Polysaccharide-Iron Complex: (Moderate) Administer cefdinir at least 2 hours before or 2 hours after iron supplements. Cefdinir absorption may be reduced. Coadministration of cefdinir with a therapeutic iron supplement containing 60 mg of elemental iron or vitamins supplemented with 10 mg of elemental iron reduced extent of absorption by 80% and 31%, respectively.
Relugolix; Estradiol; Norethindrone acetate: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Segesterone Acetate; Ethinyl Estradiol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available.
Sodium Ferric Gluconate Complex; ferric pyrophosphate citrate: (Moderate) Administer cefdinir at least 2 hours before or 2 hours after iron supplements. Cefdinir absorption may be reduced. Coadministration of cefdinir with a therapeutic iron supplement containing 60 mg of elemental iron or vitamins supplemented with 10 mg of elemental iron reduced extent of absorption by 80% and 31%, respectively.
Sodium picosulfate; Magnesium oxide; Anhydrous citric acid: (Major) Prior or concomitant use of antibiotics with sodium picosulfate; magnesium oxide; anhydrous citric acid may reduce efficacy of the bowel preparation as conversion of sodium picosulfate to its active metabolite bis-(p-hydroxy-phenyl)-pyridyl-2-methane (BHPM) is mediated by colonic bacteria. If possible, avoid coadministration. Certain antibiotics (i.e., tetracyclines and quinolones) may chelate with the magnesium in sodium picosulfate; magnesium oxide; anhydrous citric acid solution. Therefore, these antibiotics should be taken at least 2 hours before and not less than 6 hours after the administration of sodium picosulfate; magnesium oxide; anhydrous citric acid solution.
Sodium Sulfate; Magnesium Sulfate; Potassium Chloride: (Moderate) Administer cefdinir at least 2 hours before or 2 hours after magnesium sulfate. Cefdinir absorption may be reduced.
Torsemide: (Minor) Nephrotoxicity associated with cephalosporins may be potentiated by concomitant therapy with loop diuretics. Clinicians should be aware that this may occur even in patients with minor or transient renal impairment.
Warfarin: (Moderate) The concomitant use of warfarin with many classes of antibiotics, including cephalosporins, may increase the INR thereby potentiating the risk for bleeding. Inhibition of vitamin K synthesis due to alterations in the intestinal flora may be a mechanism; however, concurrent infection is also a potential risk factor for elevated INR. Additionally, certain cephalosporins (cefotetan, cefoperazone, cefamandole) are associated with prolongation of the prothrombin time due to the methylthiotetrazole (MTT) side chain at the R2 position, which disturbs the synthesis of vitamin K-dependent clotting factors in the liver. Monitor patients for signs and symptoms of bleeding. Additionally, increased monitoring of the INR, especially during initiation and upon discontinuation of the antibiotic, may be necessary.
Cefdinir is a beta-lactam antibiotic like the penicillins and is mainly bactericidal. Cefdinir inhibits the third and final stage of bacterial cell wall synthesis by preferentially binding to specific penicillin-binding proteins (PBPs) that are located inside the bacterial cell wall. Penicillin-binding proteins are responsible for several steps in the synthesis of the cell wall and are found in quantities of several hundred to several thousand molecules per bacterial cell. Penicillin-binding proteins vary among different bacterial species. Thus, the intrinsic activity of cefdinir as well as the other cephalosporins and penicillins against a particular organism depends on their ability to gain access to and bind with the necessary PBP. Like all beta-lactam antibiotics, the ability of cefdinir to interfere with PBP-mediated cell wall synthesis ultimately leads to cell lysis. Lysis is mediated by bacterial cell wall autolytic enzymes (i.e., autolysins). The relationship between PBPs and autolysins is unclear, but it is possible that the beta-lactam antibiotic interferes with an autolysin inhibitor. Bacterial resistance to cefdinir occurs as a result of hydrolysis by some beta-lactamases, alteration of the PBP, and decreased drug permeability.
Cefdinir is administered orally. Once in the systemic circulation, cefdinir is 60-70% bound to plasma proteins in both adults and children; protein binding is independent of concentration. Distribution is to various sites including the lungs, middle ear fluid, sinuses, skin blister, and tonsils. Data on cefdinir penetration into human cerebrospinal fluid (CSF) are not available. Cefdinir is not appreciably metabolized and activity is primarily due to the parent drug. Excretion is principally via renal excretion with a mean plasma elimination half-life of about 1.7 hours.
-Route-Specific Pharmacokinetics
Oral Route
Following oral administration of cefdinir capsules or oral suspension, maximal plasma concentrations occur 2-4 hours post dose. Plasma cefdinir concentrations increase with dose, but the increases are less than dose-proportional from 300 mg (7 mg/kg) to 600 mg (14 mg/kg). Cefdinir bioavailability following administration of the oral suspension to healthy adults is 120% relative to the capsules. The estimated bioavailability of cefdinir capsules is 21% following administration of a 300 mg dose, and 16% following administration of a 600 mg dose. Estimated absolute bioavailability of cefdinir oral suspension is 25%. The rate (Cmax) and extent (AUC) of cefdinir absorption from the capsules are reduced by 16% and 10%, respectively, when given with a high-fat meal, however, the magnitude of these reductions is not likely to be clinically significant. Therefore, cefdinir may be taken without regard to meals.
-Special Populations
Hepatic Impairment
Because cefdinir is predominantly renally eliminated and not appreciably metabolized, studies in patients with hepatic impairment have not been conducted. Dosage adjustment is not expected to be required in this population.
Renal Impairment
Cefdinir pharmacokinetics have been studied in patients with varying degrees of renal impairment. Decreases in cefdinir elimination rate, apparent oral clearance, and renal clearance were proportional to the reduction in creatinine clearance (CrCl). As a result, plasma cefdinir concentrations were higher and persisted longer in subjects with renal impairment than in those without renal impairment. In subjects with CrCl 30 to 60 mL/min, the Cmax and T1/2 increased by approximately 2 fold and AUC by approximately 3 fold. In subjects with CrCl < 30 mL/min, Cmax increased by approximately 2 fold, T1/2 by approximately 5 fold, and AUC by approximately 6 fold. Dosage adjustment is recommended in patients with creatinine clearance < 30 mL/min. Hemodialysis (4 hours duration) removed 63% of cefdinir from the body and reduced apparent elimination T1/2 from 16 (+/- 3.5) to 3.2 (+/- 1.2) hours. Dosage adjustments are recommended in patients undergoing hemodialysis.
Pediatrics
Infants and Children
Clearance is higher in younger children (< 3 years of age) compared with older children (3 to 12 years of age). Elimination half-life has been reported to be 1.3 and 1.6 hours, respectively.
Geriatric
The effect of age on cefdinir pharmacokinetics after a single 300 mg oral dose was evaluated in 32 subjects 19 to 91 years of age. Systemic exposure to cefdinir was substantially increased in older subjects, Cmax by 44% and AUC by 86%. The increases were due to a reduction in cefdinir clearance. The apparent volume of distribution was also reduced, thus no appreciable alterations in apparent elimination T1/2 were observed in the elderly vs young adults. Cefdinir clearance is primarily related to changes in renal function rather than age, so elderly patients do not require dosage adjustment unless they have markedly compromised renal function (creatinine clearance < 30 mL/min).
Gender Differences
The results of a meta-analysis of clinical pharmacokinetics indicated no significant impact of gender on cefdinir pharmacokinetics.
Ethnic Differences
The results of a meta-analysis of clinical pharmacokinetics indicated no significant impact of race on cefdinir pharmacokinetics.