Imipenem is a beta-lactam antibiotic derived from thienamycin and is the first drug to be classified as a carbapenem antibiotic. Cilastatin is added as an inhibitor of dehydropeptidase-1, an enzyme found in the renal tubule border that metabolizes imipenem. Without cilastatin, imipenem is rapidly metabolized and causes toxicity to the proximal tubule. Cilastatin itself has no antibacterial activity. Imipenem possesses several traits that make it an effective antibiotic including: a) more efficient penetration through the bacterial cell wall, b) resistance to bacterial enzymes, and c) affinity for all bacterial PBPs. Imipenem has a broader spectrum of activity than do many other beta-lactam antibiotics. Clinically, the combination of imipenem-cilastatin is used to treat severe or resistant infections, especially those that are nosocomial in origin. The FDA approved imipenem-cilastatin in November 1985.
General Administration Information
For storage information, see the specific product information within the How Supplied section.
Tuberculosis patients*
-Directly observed therapy (DOT) is recommended for all children as well as adolescents and adults living with HIV.
Route-Specific Administration
Injectable Administration
-Visually inspect parenteral products for particulate matter and discoloration prior to administration whenever solution and container permit.
Intravenous Administration
Reconstitution and Dilution
-Do not use diluents containing benzyl alcohol for reconstitution when administering to neonates due to toxicity.
-Reconstitute the vial with 10 mL of a compatible solution, including 0.9% Sodium Chloride Injection, 5% Dextrose Injection, 5% Dextrose and 0.9% Sodium Chloride Injection, and 5% Dextrose with 0.225% or 0.45% Sodium Chloride Injection.
-Shake well.
-Further dilution is required prior to administration. Do not administer the reconstituted suspension by direct intravenous infusion.
-Transfer the reconstituted suspension to 100 mL of an appropriate infusion solution. Smaller pediatric patients may require less volume; maximum concentration for final administration is 5 mg/mL.
-Repeat transfer of the resulting suspension with an additional 10 mL of infusion solution to ensure complete transfer of vial contents to the infusion solution and agitate the resulting mixture until clear.
-Storage: Reconstituted solutions maintain potency for 4 hours at room temperature or 24 hours under refrigeration. Do not freeze.
Intermittent IV Infusion:
-Infusion rate is dependent on the dose. Infuse doses of 500 mg or less over 20 to 30 minutes. Infuse doses more than 500 mg over 40 to 60 minutes.
-The infusion rate may be slowed in patients who develop nausea during the infusion.
-Storage: Discard unused portion of the infusion solution when applicable.
Intermittent Extended IV Infusion*:
NOTE: Administration by extended infusion is not FDA-approved.
-Administering as an extended infusion (3-hour infusion) may increase the likelihood of pharmacodynamic target achievement in difficult to treat infections.
Nausea (2% adults), vomiting (1.5% adults; 1.1% pediatrics), diarrhea (1.8% adults; 3% to 3.9% pediatrics), and gastroenteritis (less than 2% adults; 1.1% pediatrics) were among the most frequent adverse reactions reported in patients receiving imipenem in clinical trials. If nausea is experienced during administration, the infusion rate may be slowed. Other gastrointestinal adverse reactions reported in less than 0.2% of adult patients in clinical trials include hemorrhagic colitis, abdominal pain, glossitis, tongue papillar hypertrophy, pyrosis (heartburn), pharyngeal pain, and hypersalivation. Tooth discoloration, tongue discoloration, and taste perversion (dysgeusia) were reported during postmarketing surveillance.
A local injection site reaction, including phlebitis (3.1% adults; 2.2% pediatrics), can occur after IV administration of imipenem. Erythema at the injection site (0.4%) and vein induration (0.2%) were also reported in adult patients. Pain at the injection site was reported in 0.7% of patients receiving IV therapy. Pediatric patients also reported irritation at the IV site (1.1%).
Imipenem has been associated with adverse CNS effects, including confusion (less than 0.2%), myoclonia (less than 0.2%), and seizures. Seizures have been reported in 0.4% of adults and 5.9% of pediatric patients 3 months of age and younger receiving imipenem in clinical trials. Seizures are more likely to occur in elderly patients, patients with a history of a CNS disorder, a history of seizures, significant renal impairment, and in cases in which the recommended dosage is exceeded; however, seizures have also occurred in patients with none of these risk factors. In addition, imipenem is not recommended for the treatment of CNS infections in pediatric patients because of the increased seizure risk. Additive CNS toxicity also has occurred in patients receiving imipenem in combination with other drugs. Dizziness (0.3%) and drowsiness (0.2%) were reported in adult patients in clinical trials. Additional adverse reactions reported in less than 0.2% of adult patients in clinical trials include encephalopathy, paresthesias, vertigo, and headache. Tremor, psychic disturbances, hallucinations, agitation, and dyskinesia were reported during postmarketing surveillance.
Elevated hepatic enzymes, including elevated AST and ALT, were reported in patients receiving imipenem in clinical trials. Hyperbilirubinemia, decreased bilirubin, and increased alkaline phosphatase were also reported. Other adverse reactions reported in adult patients in clinical trials or during postmarketing surveillance include hepatitis (including fulminant hepatitis), hepatic failure, jaundice, and elevated LDH.
Imipenem has been associated with acute generalized exanthematous pustulosis (AGEP). The non-follicular, pustular, erythematous rash starts suddenly and is associated with fever above 38 degrees C. Drugs are the main cause of AGEP. A period of 2 to 3 weeks after an inciting drug exposure appears necessary for a first episode of AGEP. Unintentional reexposure may cause a second episode within 2 days.
Rash (0.9% adults; 1.5% to 2.2% pediatrics), pruritus (0.3% adults), and urticaria (0.2% adults) were reported in patients receiving imipenem in clinical trials. Other adverse reactions reported in less than 0.2% of adult patients during clinical trials include erythema multiforme, angioneurotic edema (angioedema), flushing, cyanosis, hyperhidrosis, skin texture changes, and pruritus vulvae. Stevens-Johnson syndrome and toxic epidermal necrolysis were reported during postmarketing surveillance. Anaphylactoid reactions have been reported with beta-lactam therapy.
Cardiovascular adverse events reported with imipenem use in trials include hypotension (0.4% adults), palpitations (less than 0.2% adults), and sinus tachycardia (less than 0.2% adults; 1.5% pediatrics).
Fever was reported in 0.5% of adult patients receiving imipenem in clinical trials. Other generalized adverse reactions reported in less than 0.2% of adult patients in clinical trials include polyarthralgia/arthralgia, asthenia, and weakness. Drug fever was reported during postmarketing surveillance.
Hematologic adverse reactions reported in adult or pediatric patients during imipenem clinical trials include eosinophilia, thrombocytosis, decreased hemoglobin, and decreased hematocrit. Hematologic adverse reactions reported in pediatric patients during imipenem clinical trials include neutropenia, thrombocytopenia, and increased hematocrit. Other hematologic adverse reactions noted in adults during clinical trials or during postmarketing surveillance include increased white blood cells, pancytopenia, bone marrow depression, neutropenia, leukopenia, hemolytic anemia, positive Coombs test, agranulocytosis, increased monocytes, abnormal prothrombin time, increased lymphocytes, increased basophils, and decreased erythrocytes.
Hearing loss and tinnitus have been reported in less than 0.2% of adult patients during imipenem clinical trials.
Respiratory and related adverse reactions reported in less than 0.2% of adult patients during imipenem clinical trials include chest discomfort/chest pain (unspecified), dyspnea, hyperventilation, and thoracic spine pain.
Urinary and renal adverse reactions reported during imipenem clinical trials include oliguria (less than 0.2% adults; 2.2% pediatrics), anuria (less than 0.2% adults; 2.2% pediatrics), increased serum creatinine, and the presence of urine protein (proteinuria). Urine discoloration (1.1%) was reported in pediatric patients during imipenem clinical trials. Other adverse reactions reported in less than 0.2% of adult patients in clinical trials or during postmarketing surveillance include acute renal failure (unspecified), increased BUN (azotemia), polyuria, and abnormalities in the urinalysis (presence of red blood cells, white blood cells, casts, bilirubin, and urobilinogen).
Microbial overgrowth and superinfection can occur with antibiotic use. C. difficile-associated diarrhea (CDAD) or pseudomembranous colitis (less than 0.2%) has been reported with imipenem. 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 was reported in less than 0.2% of adults, and oral candidiasis was reported in 1.5% of pediatric patients during clinical trials. Infused vein infection was reported in less than 0.2% of adult patients during IV infusion.
Electrolyte abnormalities reported in adult patients receiving imipenem in clinical trials include hyponatremia, hyperkalemia, and hyperchloremia.
Imipenem; cilastatin is contraindicated in patients with a carbapenem hypersensitivity. Imipenem; cilastatin should be used cautiously in patients with penicillin hypersensitivity, cephalosporin hypersensitivity, or sensitivity to other beta-lactams (e.g., aztreonam, loracarbef). Although imipenem has been used safely in these patients, imipenem is structurally similar to the penicillins and cephalosporins, causing these patients to be more susceptible to hypersensitivity reactions.
Use imipenem cautiously in patients with brain lesions, a history of seizure disorder, or other neurological disease or condition that may lower the seizure threshold, such as head trauma. In addition, the manufacturer warns against use of imipenem in pediatric patients with CNS infections due to the increased risk of seizures. The risk of imipenem-induced seizures increases when imipenem is given at doses higher than recommended. Imipenem also should be used cautiously in patients receiving drugs when potential CNS effects may be additive.
Patients with impaired renal function are known to be at increased risk for toxicity, specifically seizures. Adult patients with a CrCl <= 30 mL/minute are particularly at risk; the threshold for increased risk in pediatric patients is not known. Due to a lack of data and increased risk of toxicity, the FDA-approved labeling recommends against the use of imipenem in pediatric patients weighing less than 30 kg with renal impairment. Adult patients with a CrCl < 90 mL/minute and pediatric patients with a CrCl <= 50 mL/minute require adjustments of their imipenem dose. The FDA-approved labeling recommends that adult patients with renal failure (CrCl < 15 mL/minute) should not receive imipenem unless hemodialysis is instituted within 48 hours. For patients receiving dialysis, imipenem therapy should only be continued if the benefit outweighs the risk.
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 imipenem; cilastatin, 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.
Available data from a small number of postmarketing cases with imipenem use in pregnancy are not sufficient to identify any drug-associated risks for major birth defects, miscarriage, or adverse maternal or fetal outcomes. A small study showed that imipenem crossed the placenta with amniotic fluid concentrations averaging approximately 47% (+/- 39%) of the maternal concentration in plasma. The imipenem mean concentration in umbilical venous and arterial blood averaged approximately 33% (+/- 12%) and 31% (+/- 13%) of maternal blood concentrations, respectively. Animal developmental toxicity studies with imipenem; cilastatin revealed no evidence of teratogenicity. When imipenem; cilastatin 100 mg/kg/day IV (0.6-times the maximum recommended human daily dose) was given to pregnant cynomolgus monkeys, an increase in embryonic loss was observed. An imipenem; cilastatin dose of 40 mg/kg IV given to pregnant cynomolgus monkeys caused significant maternal toxicity including death and embryofetal loss.
There are insufficient data on the presence of imipenem; cilastatin in human breast milk, and no data on the effects on the breast-fed child, or the effects on milk production. In general, unless the infant is allergic to imipenem, breast-feeding is likely safe during maternal carbapenem therapy; observe the infant for potential effects. Consider the developmental and health benefits of breast-feeding along with the mother's clinical need for imipenem; cilastatin and any potential adverse effects from imipenem; cilastatin or the underlying maternal condition.
Imipenem; cilastatin is known to be substantially excreted by the kidney, and the risk of toxic reactions is greater in geriatric adults with impaired renal function. Care should be taken in dose selection, and it may be useful to monitor renal function. Dosages must be adjusted for renal impairment in these patients.
Imipenem; cilastatin use may result in laboratory test interference. A false-positive reaction for glucose in the urine has been observed in patients receiving imipenem and using copper-reduction tests (e.g., Benedict's solution, Fehling's solution, and Clinitest tablets). This reaction, however, has not been observed with glucose oxidase tests (e.g., Tes-tape, Clinistix, Diastix). Additionally, a positive Coombs' test has been observed during imipenem; cilastatin use.
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: Acinetobacter calcoaceticus, Acinetobacter sp., Aeromonas hydrophila, Alcaligenes sp., Bacillus sp., Bacteroides fragilis, Bacteroides intermedius, Bacteroides sp., Bacteroides thetaiotaomicron, Bifidobacterium sp., Capnocytophaga sp., Citrobacter sp., Clostridium perfringens, Clostridium sp., Enterobacter cloacae, Enterobacter sp., Enterococcus faecalis, Escherichia coli, Eubacterium sp., Fusobacterium sp., Gardnerella vaginalis, Haemophilus ducreyi, Haemophilus influenzae (beta-lactamase negative), Haemophilus influenzae (beta-lactamase positive), Haemophilus parainfluenzae, Klebsiella oxytoca, Klebsiella pneumoniae, Klebsiella sp., Listeria monocytogenes, Morganella morganii, Neisseria gonorrhoeae, Nocardia sp., Pantoea agglomerans, Parabacteroides distasonis, Pasteurella sp., Peptococcus sp., Peptostreptococcus sp., Prevotella bivia, Prevotella disiens, Prevotella melaninogenica, Propionibacterium sp., Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, Providencia stuartii, Pseudomonas aeruginosa, Serratia marcescens, Serratia sp., Staphylococcus aureus (MSSA), Staphylococcus epidermidis, Staphylococcus saprophyticus, Streptococcus agalactiae (group B streptococci), Streptococcus pneumoniae, Streptococcus pyogenes (group A beta-hemolytic streptococci), Streptococcus sp. (Group C), Streptococcus sp. (Group G), Veillonella sp., 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 intraabdominal infections, including peritonitis, appendicitis, intraabdominal abscess, biliary tract infections (cholecystitis, cholangitis), and peritoneal dialysis-related peritonitis*:
-for the treatment of complicated community-acquired, healthcare-acquired, or hospital-acquired intraabdominal infections with adequate source control:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 8 hours for fully susceptible organisms and 1 g IV every 6 hours for organisms with intermediate susceptibility. Treat for 3 to 7 days. Complicated infections include peritonitis and appendicitis complicated by rupture, and intraabdominal abscess.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose IV every 6 hours (Max: 2 g/day for fully susceptible organisms; 4 g/day for moderately susceptible organisms). Treat for 3 to 7 days. Complicated infections include peritonitis and appendicitis complicated by rupture, and intraabdominal abscess.
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours for 3 to 7 days. Complicated infections include peritonitis and appendicitis complicated by rupture, and intraabdominal abscess.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours for 7 to 10 days.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours for 7 to 10 days.
-for the treatment of complicated community-acquired, healthcare-acquired, or hospital-acquired intraabdominal infections with adequate source control due to resistant gram-negative organisms using extended-infusion dosing*:
Intravenous dosage:
Adults: 500 mg IV administered over 3 hours every 6 hours for 3 to 7 days. Complicated infections include peritonitis and appendicitis complicated by rupture, and intraabdominal abscess.
-for the treatment of uncomplicated intraabdominal infections:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 6 to 8 hours. Antibiotics should be discontinued within 24 hours. Uncomplicated infections include acute appendicitis without perforation, abscess, or local peritonitis; traumatic bowel perforations repaired within 12 hours; acute cholecystitis without perforation; and ischemic, non-perforated bowel.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose IV every 6 hours (Max: 4 g/day). Antibiotics should be discontinued within 24 hours. Uncomplicated infections include acute appendicitis without perforation, abscess, or local peritonitis; traumatic bowel perforations repaired within 12 hours; acute cholecystitis without perforation; and ischemic, non-perforated bowel.
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours. Antibiotics should be discontinued within 24 hours. Uncomplicated infections include acute appendicitis without perforation, abscess, or local peritonitis; traumatic bowel perforations repaired within 12 hours; acute cholecystitis without perforation; and ischemic, non-perforated bowel.
-for the treatment of peritoneal dialysis-related peritonitis*:
Intermittent Intraperitoneal dosage*:
Adults: 500 mg intraperitoneally in alternate exchanges for 21 to 28 days.
Continuous Intraperitoneal dosage*:
Adults: 250 mg/L intraperitoneal loading dose, followed by 50 mg/L in each dialysate exchange. Treat for 21 to 28 days.
Infants, Children, and Adolescents: 250 mg/L intraperitoneal loading dose, followed by 50 mg/L in each dialysate exchange. Treat for 14 to 21 days.
For the treatment of urinary tract infection (UTI), including cystitis and pyelonephritis:
-for the treatment of nonspecific UTI due to susceptible organisms:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 8 hours.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose IV every 6 hours (Max: 2 g/day).
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours.
-for the treatment of nonspecific UTI due to organisms with intermediate susceptibility:
Intravenous dosage:
Adults: 1 g IV every 6 hours.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose IV every 6 hours (Max: 4 g/day).
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours.
-for the treatment of uncomplicated cystitis due to infections with difficult-to-treat resistance:
Intravenous dosage:
Adults: 500 mg IV every 6 hours for 3 to 7 days.
-for the treatment of pyelonephritis due to susceptible organisms:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 8 hours for 7 to 14 days.
-for the treatment of pyelonephritis due to organisms with intermediate susceptibility:
Intravenous dosage:
Adults: 1 g IV every 6 hours for 7 to 14 days.
-for the treatment of complicated UTI, including pyelonephritis, due to infections with difficult-to-treat resistance using extended-infusion dosing*:
Intravenous dosage:
Adults: 500 mg administered over 3 hours IV every 6 hours for 7 to 14 days.
For the empiric treatment of febrile neutropenia*:
-for the empiric treatment of febrile neutropenia in adults:
Intravenous dosage:
Adults: 500 mg IV every 6 hours has been used successfully in studies. An antipseudomonal beta-lactam, such as a carbapenem, is recommended by guidelines as first line therapy in neutropenic adults.
-for the empiric treatment of febrile neutropenia in pediatric patients:
Intravenous dosage:
Infants, Children, and Adolescents: 15 to 25 mg/kg/dose IV every 6 hours. Imipenem has been successfully used for the empiric treatment of febrile neutropenia in children. Guidelines for the management of fever and neutropenia in cancer patients recommend monotherapy with an antipseudomonal beta-lactam or a carbapenem as empiric treatment in high-risk patients; addition of a second gram-negative antimicrobial agent (i.e., aminoglycoside, aztreonam) is recommended for patients who are clinically unstable, when a resistant infection is suspected, or for centers with high rates of resistant pathogens.
For the treatment of pulmonary exacerbations in patients with cystic fibrosis*:
Intravenous dosage:
Adults: 1 g IV every 6 hours. Imipenem has improved clinical outcomes in small, observational studies in CF patients with acute pulmonary exacerbations; however, a high rate of emergence to Pseudomonas has been observed. The Cystic Fibrosis Foundation recommends a carbapenem as the beta-lactam choice for patients with a cephalosporin sensitivity or multidrug-resistant organisms.
Children and Adolescents: 25 mg/kg/dose IV every 6 hours (Max: 1 g/dose). Imipenem has improved clinical outcomes in small, observational studies in CF patients with acute pulmonary exacerbations; however, a high rate of emergence to Pseudomonas has been observed. The Cystic Fibrosis Foundation recommends a carbapenem as the beta-lactam choice for patients with a cephalosporin sensitivity or multidrug-resistant organisms.
For the treatment of lower respiratory tract infections (LRTIs), including community-acquired pneumonia (CAP) and nosocomial pneumonia:
-for the treatment of unspecified LRTIs due to susceptible organisms:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 8 hours.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose IV every 6 hours (Max: 2 g/day).
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours.
-for the treatment of unspecified LRTIs due to organisms with intermediate susceptibility:
Intravenous dosage:
Adults: 1 g IV every 6 hours.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose IV every 6 hours (Max: 4 g/day).
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours.
-for the treatment of LRTIs due to resistant gram-negative organisms using extended-infusion dosing*:
Intravenous dosage:
Adults: 500 mg administered over 3 hours IV every 6 hours.
-for the treatment of community-acquired pneumonia (CAP):
Intravenous dosage:
Adults: 500 mg IV every 6 hours for at least 7 days as part of combination therapy.
Adolescents: 15 to 25 mg/kg/dose IV every 6 hours (Max: 2 g/day) for 5 to 7 days. In persons living with HIV, imipenem; cilastatin is recommended as part of combination therapy for hospitalized patients at risk for P. aeruginosa.
-for the treatment of nosocomial pneumonia:
Intravenous dosage:
Adults: 500 mg IV every 6 hours for 7 days as a singular agent or as part of combination therapy.
For the treatment of skin and skin structure infections, including cellulitis, erysipelas, necrotizing infections, diabetic foot ulcer, pyomyositis, and surgical incision site infections:
-for the treatment of unspecified skin infections due to susceptible organisms:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 8 hours.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose (Max: 500 mg/dose) IV every 6 hours.
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours.
-for the treatment of unspecified skin infections due to organisms with intermediate susceptibility:
Intravenous dosage:
Adults: 1 g IV every 6 hours.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose (Max: 1 g/dose) IV every 6 hours.
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours.
-for the treatment of unspecified skin infections due to resistant gram-negative organisms using extended-infusion dosing*:
Intravenous dosage:
Adults: 500 mg IV administered over 3 hours every 6 hours.
-for the treatment of severe nonpurulent skin infections, such as cellulitis and erysipelas:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 8 hours for fully susceptible organisms and 1 g IV every 6 hours for organisms with intermediate susceptibility for 5 to 14 days.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose (Max: 1 g/dose) IV every 6 hours for 5 to 14 days.
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours for 5 to 14 days.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours for 5 to 14 days.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours for 5 to 14 days.
-for the treatment of necrotizing infections of the skin, fascia, and muscle:
Intravenous dosage:
Adults: 1 g IV every 6 to 8 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for mixed necrotizing infections.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose (Max: 1 g/dose) IV every 6 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for mixed necrotizing infections.
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for mixed necrotizing infections.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours for mixed necrotizing infections.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours until further debridement is not necessary, the patient has improved clinically, and fever has been absent for 48 to 72 hours.
-for the treatment of diabetic foot ulcer:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 8 hours for fully susceptible organisms and 1 g IV every 6 hours for organisms with intermediate susceptibility for 7 to 14 days for moderate or severe infections in patients with risk factors for resistant gram negative rods, ischemic limb/necrotizing/gas forming infections, or a macerated ulcer or in a warm climate. Continue treatment for up to 28 days if infection is improving but is extensive and resolving slower than expected or if patient has severe peripheral artery disease.
-for the treatment of pyomyositis:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 8 hours for fully susceptible organisms and 1 g IV every 6 hours for organisms with intermediate susceptibility for 14 to 21 days plus vancomycin in patients with underlying conditions.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose (Max: 1 g/dose) IV every 6 hours for 14 to 21 days plus vancomycin in patients with underlying conditions.
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours for 14 to 21 days plus vancomycin in patients with underlying conditions.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours for 14 to 21 days plus vancomycin in patients with underlying conditions.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours for 14 to 21 days plus vancomycin in patients with underlying conditions.
-for the treatment of surgical incision site infections:
Intravenous dosage:
Adults: 500 mg IV every 6 hours for incisional surgical site infections of the intestinal or genitourinary tract.
For the treatment of bone and joint infections, including osteomyelitis, infectious arthritis, orthopedic device-related infection*, and infections with difficult-to-treat resistance:
-for the treatment of osteomyelitis due to susceptible organisms:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 8 hours for 4 to 6 weeks.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose IV every 6 hours (Max: 2 g/day). Treat for 2 to 4 days or until clinically improved, followed by oral step-down therapy for a total duration of 3 to 4 weeks for uncomplicated cases. A longer course (i.e., 4 to 6 weeks or longer) may be needed for severe or complicated infections.
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
-for the treatment of osteomyelitis due to organisms with intermediate susceptibility:
Intravenous dosage:
Adults: 1 g IV every 6 hours for 4 to 6 weeks.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose IV every 6 hours (Max: 4 g/day). Treat for 2 to 4 days or until clinically improved, followed by oral step-down therapy for a total duration of 3 to 4 weeks for uncomplicated cases. A longer course (i.e., 4 to 6 weeks or longer) may be needed for severe or complicated infections.
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
-for the treatment of infectious arthritis due to susceptible organisms:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 8 hours. Treat for 1 to 2 weeks or until clinically improved, followed by oral step-down therapy for 2 to 4 weeks.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose IV every 6 hours (Max: 2 g/day). Treat for 2 to 4 days or until clinically improved, followed by oral step-down therapy for a total duration of 2 to 3 weeks for uncomplicated cases. A longer course (i.e., 4 to 6 weeks or longer) may be needed for septic hip arthritis or severe or complicated infections.
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
-for the treatment of infectious arthritis due to organisms with intermediate susceptibility:
Intravenous dosage:
Adults: 1 g IV every 6 hours. Treat for 1 to 2 weeks or until clinically improved, followed by oral step-down therapy for 2 to 4 weeks.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose IV every 6 hours (Max: 4 g/day). Treat for 2 to 4 days or until clinically improved, followed by oral step-down therapy for a total duration of 2 to 3 weeks for uncomplicated cases. A longer course (i.e., 4 to 6 weeks or longer) may be needed for septic hip arthritis or severe or complicated infections.
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours. Treat for 14 to 21 days or until clinically improved, followed by oral step-down therapy for a total duration of 4 to 6 weeks. A longer course (several months) may be needed for severe or complicated infections.
-for the treatment of prosthetic joint infection* due to susceptible organisms:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 8 hours. Treat for 4 to 6 weeks as first-line therapy for infections due to P. aeruginosa or Enterobacterales, which may be followed by long-term suppressive therapy. May consider addition of an aminoglycoside for P. aeruginosa infections; if aminoglycoside is in spacer and organism is aminoglycoside-susceptible, then double coverage is provided with IV or oral monotherapy.
-for the treatment of prosthetic joint infection* due to organisms with intermediate susceptibility:
Intravenous dosage:
Adults: 1 g IV every 6 hours for organisms with intermediate susceptibility. Treat for 4 to 6 weeks as first-line therapy for infections due to P. aeruginosa or Enterobacterales, which may be followed by long-term suppressive therapy. May consider addition of an aminoglycoside for P. aeruginosa infections; if aminoglycoside is in spacer and organism is aminoglycoside-susceptible, then double coverage is provided with IV or oral monotherapy.
-for the treatment of bone and joint infections with difficult-to-treat resistance using extended infusion dosing*:
Intravenous dosage:
Adults: 500 mg administered over 3 hours IV every 6 hours.
For the treatment of gynecologic infections:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 8 hours for fully susceptible organisms and 1 g IV every 6 hours for organisms with intermediate susceptibility.
Children and Adolescents : 15 to 25 mg/kg/dose IV every 6 hours (Max: 2 g/day for fully susceptible organisms; 4 g/day for moderately susceptible organisms).
For the treatment of anthrax*:
-for the treatment of cutaneous anthrax* without aerosol exposure or signs and symptoms of meningitis:
Intravenous dosage:
Adults: 1 g IV every 6 hours for 7 to 10 days or until clinical criteria for stability are met; may consider step-down to oral therapy.
Infants, Children, and Adolescents: 25 mg/kg/dose (Max: 1 g/dose) IV every 6 hours for 7 to 10 days or until clinical criteria for stability are met; may consider step-down to oral therapy.
-for the treatment of cutaneous anthrax* with aerosol exposure and without signs and symptoms of meningitis:
Intravenous dosage:
Adults: 1 g IV every 6 hours for 7 to 10 days or until clinical criteria for stability are met; may consider step-down to oral therapy. Transition to a postexposure prophylaxis regimen to complete a 42- to 60-day total treatment course depending on vaccine status and immunocompetence.
Infants, Children, and Adolescents: 25 mg/kg/dose (Max: 1 g/dose) IV every 8 hours for 7 to 10 days or until clinical criteria for stability are met; may consider step-down to oral therapy. Transition to a postexposure prophylaxis regimen to complete a 60-day total treatment course.
-for the treatment of systemic anthrax* without aerosol exposure, including those with signs and symptoms of meningitis, as part of combination therapy:
Intravenous dosage:
Adults: 1 g IV every 6 hours for at least 14 days; may consider step-down to oral therapy.
Infants, Children, and Adolescents: 25 mg/kg/dose (Max: 1 g/dose) IV every 6 hours for at least 14 days; may consider step-down to oral therapy.
Neonates 32 weeks gestation and older: 25 mg/kg/dose IV every 8 hours for at least 14 days; may consider step-down to oral therapy.
-for the treatment of systemic anthrax* with aerosol exposure, including those with signs and symptoms of meningitis, as part of combination therapy:
Intravenous dosage:
Adults: 1 g IV every 6 hours for at least 14 days; may consider step-down to oral therapy.
Immunocompromised Adults: 1 g IV every 6 hours for at least 14 days; may consider step-down to oral therapy. Transition to a postexposure prophylaxis regimen to complete a 60-day total treatment course from illness onset.
Infants, Children, and Adolescents: 25 mg/kg/dose (Max: 1 g/dose) IV every 6 hours for at least 14 days; may consider step-down to oral therapy.
Immunocompromised Infants, Children, and Adolescents: 25 mg/kg/dose (Max: 1 g/dose) IV every 6 hours for at least 14 days; may consider step-down to oral therapy. Transition to a postexposure prophylaxis regimen to complete a 60-day total treatment course from illness onset.
Neonates 32 weeks gestation and older: 25 mg/kg/dose IV every 8 hours for at least 14 days; may consider step-down to oral therapy. Transition to a postexposure prophylaxis regimen to complete a 60-day total treatment course from illness onset.
For the treatment of melioidosis* due to Burkholderia pseudomallei:
Intravenous dosage:
Adults: 60 to 100 mg/kg/day IV in divided doses (25 mg/kg/dose every 6 hours or 20 mg/kg/dose every 8 hours; Max: 1 g/dose) for at least 10 to 14 days and clinical improvement is achieved. After intensive IV therapy, follow with at least 3 months of eradication therapy with oral agents (e.g., trimethoprim/sulfamethoxazole 8 mg/40 mg/kg/dose PO every 12 hours [Max: 320 mg/1,600 mg/dose] +/- doxycycline 2 mg/kg/dose PO every 12 hours [Max: 100 mg/dose]).
Infants, Children, and Adolescents: 60 to 100 mg/kg/day IV in divided doses (25 mg/kg/dose every 6 hours or 20 mg/kg/dose every 8 hours; Max: 1 g/dose) for at least 10 to 14 days and clinical improvement is achieved. After intensive IV therapy, follow with at least 3 months of eradication therapy with oral agents (e.g., trimethoprim/sulfamethoxazole 8 mg/40 mg/kg/dose PO every 12 hours [Max: 320 mg/1,600 mg/dose] +/- doxycycline 2 mg/kg/dose PO every 12 hours [Max: 100 mg/dose]).
For the treatment of bacteremia and sepsis, including infections due to organisms with difficult-to-treat resistance*:
-for the treatment of bacteremia and sepsis due to susceptible organisms:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 8 hours. Start within 1 hour for septic shock or within 3 hours for possible sepsis without shock. Duration of therapy is not well-defined and dependent on patient- and infection-specific factors. Assess patient daily for deescalation of antimicrobial therapy based on pathogen identification and/or adequate clinical response.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose IV every 6 hours (Max: 2 g/day). Start within 1 hour for septic shock or within 3 hours for sepsis-associated organ dysfunction without shock. Duration of therapy is not well-defined and dependent on patient- and infection-specific factors. Assess patient daily for deescalation of antimicrobial therapy based on pathogen identification and/or adequate clinical response.
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours. Start within 1 hour for septic shock or within 3 hours for sepsis-associated organ dysfunction without shock. Duration of therapy is not well-defined and dependent on patient- and infection-specific factors. Assess patient daily for deescalation of antimicrobial therapy based on pathogen identification and/or adequate clinical response.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours. Start within 1 hour for septic shock or within 3 hours for sepsis-associated organ dysfunction without shock. Duration of therapy is not well-defined and dependent on patient- and infection-specific factors. Assess patient daily for deescalation of antimicrobial therapy based on pathogen identification and/or adequate clinical response. Neonates younger than 37 weeks gestational age were excluded from guideline scope.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours. Start within 1 hour for septic shock or within 3 hours for sepsis-associated organ dysfunction without shock. Duration of therapy is not well-defined and dependent on patient- and infection-specific factors. Assess patient daily for deescalation of antimicrobial therapy based on pathogen identification and/or adequate clinical response. Neonates younger than 37 weeks gestational age were excluded from guideline scope.
-for the treatment of bacteremia and sepsis due to organisms with intermediate susceptibility:
Intravenous dosage:
Adults: 1 g IV every 6 hours. Start within 1 hour for septic shock or within 3 hours for possible sepsis without shock. Duration of therapy is not well-defined and dependent on patient- and infection-specific factors. Assess patient daily for deescalation of antimicrobial therapy based on pathogen identification and/or adequate clinical response.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose IV every 6 hours (Max: 4 g/day). Start within 1 hour for septic shock or within 3 hours for sepsis-associated organ dysfunction without shock. Duration of therapy is not well-defined and dependent on patient- and infection-specific factors. Assess patient daily for deescalation of antimicrobial therapy based on pathogen identification and/or adequate clinical response.
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours. Start within 1 hour for septic shock or within 3 hours for sepsis-associated organ dysfunction without shock. Duration of therapy is not well-defined and dependent on patient- and infection-specific factors. Assess patient daily for deescalation of antimicrobial therapy based on pathogen identification and/or adequate clinical response.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours. Start within 1 hour for septic shock or within 3 hours for sepsis-associated organ dysfunction without shock. Duration of therapy is not well-defined and dependent on patient- and infection-specific factors. Assess patient daily for deescalation of antimicrobial therapy based on pathogen identification and/or adequate clinical response. Neonates younger than 37 weeks gestational age were excluded from guideline scope.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours. Start within 1 hour for septic shock or within 3 hours for sepsis-associated organ dysfunction without shock. Duration of therapy is not well-defined and dependent on patient- and infection-specific factors. Assess patient daily for deescalation of antimicrobial therapy based on pathogen identification and/or adequate clinical response. Neonates younger than 37 weeks gestational age were excluded from guideline scope.
-for the treatment of bacteremia and sepsis due to organisms with difficult-to-treat resistance using extended-infusion dosing*:
Intravenous dosage:
Adults: 500 mg administered over 3 hours IV every 6 hours. Start within 1 hour for septic shock or within 3 hours for possible sepsis without shock. Duration of therapy is not well-defined and dependent on patient- and infection-specific factors. Assess patient daily for deescalation of antimicrobial therapy based on pathogen identification and/or adequate clinical response.
For the treatment of endocarditis:
-for the treatment of endocarditis due to susceptible organisms:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 8 hours. Guidelines suggest combination therapy with a beta-lactam, including carbapenems, and either an aminoglycoside or fluoroquinolone for 6 weeks as reasonable for endocarditis due to non-HACEK gram negative bacilli.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose IV every 6 hours (Max: 2 g/day).
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours.
-for the treatment of endocarditis due to organisms with intermediate susceptibility:
Intravenous dosage:
Adults: 1 g IV every 6 hours. Guidelines suggest combination therapy with a beta-lactam, including carbapenems, and either an aminoglycoside or fluoroquinolone for 6 weeks as reasonable for endocarditis due to non-HACEK gram negative bacilli.
Infants, Children, and Adolescents 3 months to 17 years: 15 to 25 mg/kg/dose IV every 6 hours (Max: 4 g/day).
Infants 1 to 2 months: 25 mg/kg/dose IV every 6 hours.
Neonates older than 7 days: 25 mg/kg/dose IV every 8 hours.
Neonates 0 to 7 days: 25 mg/kg/dose IV every 12 hours.
-for the treatment of endocarditis due to resistant gram-negative organisms using extended-infusion dosing*:
Intravenous dosage:
Adults: 500 mg administered over 3 hours IV every 6 hours. Guidelines suggest combination therapy with a beta-lactam, including carbapenems, and either an aminoglycoside or fluoroquinolone for 6 weeks as reasonable for endocarditis due to non-HACEK gram negative bacilli.
For the treatment of drug-resistant tuberculosis infection* paired with clavulanic acid as part of combination therapy:
Intravenous dosage:
Adults: 1 g IV every 6 to 12 hours.
Infants, Children, and Adolescents: 15 to 25 mg/kg/dose (Max: 1 g/dose) IV every 6 hours.
For the treatment of severe or complicated extensively drug-resistant typhoid fever*:
Intravenous dosage:
Adults: 500 mg IV every 6 hours or 1 g IV every 8 hours for 10 to 14 days. Consider adding azithromycin for patients who do not improve.
Infants, Children, and Adolescents: 20 to 60 mg/kg/day divided every 6 to 8 hours (Max: 1 g/dose) for 10 to 14 days. Consider adding azithromycin for patients who do not improve.
Maximum Dosage Limits:
-Adults
4 g/day IV.
-Geriatric
4 g/day IV.
-Adolescents
100 mg/kg/day IV (Max: 4 g/day).
-Children
12 years : 100 mg/kg/day IV (Max: 4 g/day).
1 to 11 years: 100 mg/kg/day IV (Max: 4 g/day).
-Infants
100 mg/kg/day IV.
-Neonates
older than 7 days : 75 mg/kg/day IV.
0 to 7 days : 50 mg/kg/day IV.
Patients with Hepatic Impairment Dosing
Specific guidelines for dosage adjustments in hepatic impairment are not available; it appears that no dosage adjustments are needed.
Patients with Renal Impairment Dosing
Adult Patients
FDA-approved labeling renal adjustment (based on starting dose):
CrCl 90 mL/minute or more: no dosage adjustment necessary.
CrCl 60 to 89 mL/minute: adjust to 400 mg IV every 6 hours for starting dose of 500 mg IV every 6 hours; 500mg IV every 6 hours for starting dose of 1 g IV every 8 hours; and 750 mg IV every 8 hours for starting dose of 1 g IV every 6 hours.
CrCl 30 to 59 mL/minute: adjust to 300 mg IV every 6 hours for starting dose of 500 mg IV every 6 hours; 500mg IV every 8 hours for starting dose of 1 g IV every 8 hours; and 500 mg IV every 6 hours for starting dose of 1 g IV every 6 hours.
CrCl 15 to 29 mL/minute: adjust to 200 mg IV every 6 hours for starting dose of 500 mg IV every 6 hours; and 500mg IV every 12 hours for starting dose of 1 g IV every 6 or 8 hours.
CrCl less than 15 mL/minute: Patients should not receive imipenem; cilastatin unless hemodialysis is instituted within 48 hours.
Alternative renal adjustment:
GFR more than 50 mL/minute: no dosage adjustment necessary.
GFR 10 to 50 mL/minute: Administer 50% of the normal dose.
GFR less than 10 mL/minute: Administer 25% of the normal dose.
Pediatric Patients
The manufacturer does not recommend imipenem use in children less than 30 kg with renal impairment due to a lack of data. Other experts recommend the following adjustments based on a usual dosage of 15 to 25 mg/kg/dose IV every 6 hours. Monitor patients carefully for signs of toxicity.
CrCl more than 50 mL/minute/1.73 m2: no dosage adjustment necessary.
CrCl 30 to 50 mL/minute/1.73 m2: 7 to 13 mg/kg/dose IV every 8 hours.
CrCl 10 to 29 mL/minute/1.73 m2: 7.5 to 12.5 mg/kg/dose IV every 12 hours.
CrCl less than 10 mL/minute/1.73 m2: 7.5 to 12.5 mg/kg/dose IV every 24 hours.
NOTE: For adults with CrCl less than 15 mL/minute the manufacturer recommends against use unless hemodialysis can be instituted within 48 hours. Patients with renal dysfunction are at higher risk for toxicity.
Intermittent hemodialysis
For adults, adjust to 200 mg IV every 6 hours for starting dose of 500 mg IV every 6 hours; and 500mg IV every 12 hours for starting dose of 1 g IV every 6 or 8 hours. Administer dose after hemodialysis and at intervals timed from the end of the hemodialysis session. Other experts suggest dosing after hemodialysis. Nonrenal clearance is less in acute renal failure compared to chronic renal failure. For pediatric patients, the recommended dose is 7.5 to 12.5 mg/kg/dose IV every 24 hours given after hemodialysis.
Peritoneal dialysis
According to the manufacturer, there is inadequate information to recommend intravenous dosing in patients undergoing peritoneal dialysis. Other experts suggest dosing for a GFR less than 10 mL/minute (i.e., administer 25% of the normal dose). For intraperitoneal dosing, refer to dosing guidelines for the treatment of peritonitis.
Continuous renal replacement therapy (CRRT)
500 mg IV every 6 hours.
*non-FDA-approved indication
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.
Disulfiram: (Moderate) Disulfiram is potentially neurotoxic. Additive effects can occur if it is administered concomitantly with other neurotoxic medications including imipenem; cilastatin.
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.
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.
Ganciclovir: (Major) Avoid concomitant use of imipenem; cilastatin and ganciclovir unless the potential benefits outweigh the risks. Generalized seizures have occurred in patients who were receiving imipenem; cilastatin concomitantly with ganciclovir.
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) 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) 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 Acetate; Ethinyl Estradiol; Ferrous fumarate: (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) 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.
Probenecid: (Major) Concomitant use of imipenem and probenecid is not recommended. Probenecid competitively inhibits renal tubular secretion and causes increased serum concentrations of imipenem and prolonged half-life.
Probenecid; Colchicine: (Major) Concomitant use of imipenem and probenecid is not recommended. Probenecid competitively inhibits renal tubular secretion and causes increased serum concentrations of imipenem and prolonged half-life.
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 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.
Theophylline, Aminophylline: (Moderate) Generalized seizures have occurred in patients who were receiving imipenem-cilastatin concomitantly with aminophylline. The mechanism of this interaction is not known. Patients should be monitored for signs of CNS toxicity during coadministration. (Moderate) Generalized seizures have occurred in patients who were receiving imipenem-cilastatin concomitantly with theophylline. The mechanism of this interaction is not known. Patients should be monitored for signs of CNS toxicity during coadministration.
Valganciclovir: (Major) Avoid concomitant use of imipenem; cilastatin and valganciclovir unless the potential benefits outweigh the risks. Generalized seizures have occurred in patients who were receiving imipenem; cilastatin concomitantly with ganciclovir.
Valproic Acid, Divalproex Sodium: (Major) Avoid concomitant carbapenem and valproic acid use. Consider alternative antibacterial therapies other than carbapenems to treat infections in patients whose seizures are well controlled with valproic acid or divalproex sodium. If coadministered, monitor valproic acid concentrations. Coadministration of carbapenems with valproic acid or divalproex sodium may reduce the serum concentration of valproic acid potentially increasing the risk of breakthrough seizures. Carbapenems may inhibit the hydrolysis of valproic acid's glucuronide metabolite (VPA-g) back to valproic acid, thus decreasing valproic acid serum concentrations.
Warfarin: (Moderate) The concomitant use of warfarin with many classes of antibiotics, including carbapenems, may result in an increased 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. 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.
Imipenem, a carbapenem beta-lactam antibiotic, is mainly bactericidal. It 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. PBPs 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. PBPs vary among different bacterial species. Imipenem binds to all PBP subtypes but has highest affinity for PBP-2 and PBP 1B. At PBP-3, where cephalosporins bind, imipenem has minimal activity. Antimicrobial activity of imipenem is a result of binding to PBP-1A, PBP-1B, and PBP-2. Because little activity is exerted at PBP-3 (the protein responsible for bacterial septum formation), long, filamentous forms are not produced after imipenem exposure. PBP-2 is responsible for maintaining the rod-like shape. Binding of imipenem to PBP-2 causes bacteria to form spheroplasts or ellipsoidal cells without filament formation. Binding to PBP-1, which is responsible for formation of the cell wall, causes these cells to lyse rapidly. 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. Prevention of the autolysin response to beta-lactam antibiotic exposure through loss of autolytic activity (mutation) or inactivation of autolysin (low-medium pH) by the microorganism can lead to tolerance to the beta-lactam antibiotic resulting in bacteriostatic activity. Imipenem also has greater ability to penetrate the outer membrane of gram-negative bacteria than do the other beta-lactam antibiotics.
Beta-lactams, including imipenem, exhibit concentration-independent or time-dependent killing. In vitro and in vivo animal studies have demonstrated that the major pharmacodynamic parameter that determines efficacy for beta-lactams is the amount of time free (non-protein bound) drug concentrations exceed the minimum inhibitory concentration (MIC) of the organism (free T above the MIC). This microbiological killing pattern is due to the mechanism of action, which is acylation of PBPs. There is a maximum proportion of PBPs that can be acylated; therefore, once maximum acylation has occurred, killing rates cannot increase. Free beta-lactam concentrations do not have to remain above the MIC for the entire dosing interval. The percentage of time required for both bacteriostatic and maximal bactericidal activity is different for the various classes of beta-lactams. Carbapenems require free drug concentrations to exceed the MIC for 20% of the dosing interval for bacteriostatic activity and 40% of the dosing interval for maximal bactericidal activity. Cephalosporins require free drug concentrations to be above the MIC for 35% to 40% of the dosing interval for bacteriostatic activity and 60% to 70% of the dosing interval for bactericidal activity. Penicillins require free drug concentrations to exceed the MIC for 30% of the dosing interval to achieve bacteriostatic activity and 50% of the dosing interval to achieve bactericidal activity. Carbapenems also are reported to have a post-antibiotic effect (PAE). PAE is defined as the suppression of bacterial growth that continues after the antibiotic concentration falls below the bacterial MIC. PAE has been reported to be 1.3 to 4 hours with imipenem, 4 to 5 hours with meropenem, and 1.5 hours with ertapenem.
Cilastatin is a reversible, competitive inhibitor of dehydropeptidase-1 (DHP-1), an enzyme found in the brush border of the proximal tubular cells of the kidneys that breaks down imipenem to inactive metabolites. By inhibiting this enzyme, cilastatin prevents the renal metabolism of imipenem, which results in an increase in urinary concentrations of imipenem from 15% to 20% up to 60% to 70% and minimizes the nephrotoxicity observed when imipenem is administered alone. Cilastatin has no antimicrobial activity, nor does it interfere with imipenem's actions.
The susceptibility interpretive criteria for imipenem; cilastatin are delineated by pathogen. The MICs for Enterobacterales are defined as susceptible at 1 mcg/mL or less, intermediate at 2 mcg/mL, and resistant at 4 mcg/mL or more (based on a dosage regimen of 500 mg IV every 6 hours or 1 g IV every 8 hours). The MICs for Acinetobacter sp. are defined as susceptible at 2 mcg/mL or less, intermediate at 4 mcg/mL, and resistant at 8 mcg/mL or more (based on a dosage of 500 mg IV every 6 hours). The MICs for P. aeruginosa are defined as susceptible at 2 mcg/mL or less, intermediate at 4 mcg/mL, and resistant at 8 mcg/mL or more (based on a dosage of 500 mg IV every 6 hours or 1 g IV every 8 hours). The MICs for other non-Enterobacterales, anaerobes, B. mallei, B. pseudomallei, Aggregatibacter sp., Bacillus sp. (excluding B. anthracis) and related genera including Brevibacillus, Cohnella, Lysinibacillus, Paenibacillus, and Sporolactobacillus are defined as susceptible at 4 mcg/mL or less, intermediate at 8 mcg/mL, and resistant at 16 mcg/mL or more. The MICs for S. pneumoniae are defined as susceptible at 0.12 mcg/mL or less, intermediate at 0.25 to 0.5 mcg/mL, and resistant at 1 mcg/mL or more. For non-meningitis S. pneumoniae isolates, a penicillin MIC of 0.06 mcg/mL or less can be used to predict imipenem; cilastatin susceptibility. The MICs for H. influenzae and H. parainfluenzae are defined as susceptible at 4 mcg/mL or less. The MICs are defined for Lactobacillus sp., Cardiobacterium sp., E. corrodens, Kingella sp., Abiotrophia sp., and Granulicatella sp. as susceptible at 0.5 mcg/mL or less, intermediate at 1 mcg/mL, and resistant at 2 mcg/mL or more. The MICs are defined for Pediococcus sp. and E. rhusiopathiae as susceptible at 0.5 mcg/mL or less. The MICs are defined for Aeromonas sp. and Vibrio sp. as susceptible at 1 mcg/mL or less, intermediate at 2 mcg/mL, and resistant at 4 mcg/mL or more. A Streptococcus sp. beta-hemolytic group organism that is susceptible to penicillin can be considered susceptible to imipenem; cilastatin. Considering site of infection and appropriate imipenem; cilastatin dosing, oxacillin-susceptible Staphylococcus sp. can be considered susceptible to imipenem.
Imipenem has a high degree of stability in the presence of beta-lactamases, including both penicillinases and cephalosporinases produced by gram-negative and gram-positive bacteria. It is a potent inhibitor of beta-lactamases from certain gram-negative bacteria that may be inherently resistant to many beta-lactam antibiotics (e.g., P. aeruginosa, Serratia sp., and Enterobacter sp.).
Imipenem-cilastatin is administered intravenously. Approximately 20% of imipenem and 40% of cilastatin are protein bound. Imipenem is distributed into most body tissues and fluids including heart valve, bone, uterus, ovary, intestine, saliva, sputum, bile, as well as peritoneal, pleural, and wound fluids. However, imipenem achieves low concentrations within the CSF, and it is not indicated in the treatment of meningitis. Both imipenem and cilastatin cross the placenta. The mean volume of distribution (Vd) in adults is 0.23 to 0.31 L/kg.
When administered alone, imipenem is rapidly metabolized in the brush border of the proximal renal tubule by dehydropeptidase 1 (DHP-1); therefore, imipenem must be administered with cilastatin, a DHP-1 inhibitor, to prevent renal metabolism and proximal tubular toxicity. Cilastatin is metabolized in the kidneys to N-acetylcilastatin, which is also an inhibitor of DHP-1. When coadministered with cilastatin, up to 70% of a dose of imipenem is excreted unchanged into the urine via tubular secretion and glomerular filtration within 10 hours. Urine concentrations of imipenem more than 10 mcg/mL are seen for up to 8 hours after a 500 mg IV dose. The remainder is eliminated primarily via metabolic inactivation by nonrenal mechanisms. No accumulation of imipenem or cilastatin in the plasma or serum is noted with doses given every 6 hours in patients with normal renal function. A small percentage is excreted in breast milk. In adults, renal clearance of imipenem resembles creatinine clearance; however, in children, it exceeds creatinine clearance suggesting significant tubular secretion in younger patients. The elimination half-lives of imipenem and cilastatin are approximately 60 minutes in adult patients with normal renal function.
Affected cytochrome P450 isoenzymes: none
-Route-Specific Pharmacokinetics
Intravenous Route
Peak plasma concentrations of imipenem occur within 20 minutes after an IV dose. In adults, peak plasma concentrations of imipenem (based on antimicrobial activity) range from 21 to 58 mcg/mL for the 500 mg dose and 41 to 83 mcg/mL for the 1,000 mg dose. At these doses, plasma concentrations decline to 1 mcg/mL or less in 4 to 6 hours.
-Special Populations
Renal Impairment
The elimination half-life increases up to 4 hours for imipenem and 15 hours for cilastatin in patients with end-stage renal disease.
Hemodialysis
Both imipenem and cilastatin are removed by hemodialysis.
Continuous Venovenous Hemodialysis (CVVHD)
In a study of 6 critically ill adults receiving CVVHD at a fixed blood flow rate of 60 mL/minute, fixed dialysate flow rate of 20 mL/minute, and drainage flow rate of 1 to 3 mL/minute, the imipenem half-life was 2.79 +/- 0.3 hours and the cilastatin half-life was 6.67 +/- 0.93 hours. The authors concluded that extending the dosage interval to every 12 hours would provide appropriate blood concentrations of imipenem; cilastatin (the dose used in the study was 500 mg IV).
Pediatrics
Infants and Children
The elimination half-life of imipenem in infants and children is approximately 1 to 1.2 hours, which is similar to what has been reported in adults. The volume of distribution is approximately 0.65 L/kg, which is larger than that reported in adults (0.25 L/kg).
Neonates
The elimination half-life of imipenem is longest in premature neonates and decreases with increasing age. The imipenem elimination half-life is approximately 2.5 hours and 1.5 to 2 hours in premature and term neonates, respectively. The volume of distribution is approximately 0.5 L/kg in premature neonates and 0.35 to 0.4 L/kg in term neonates. One pharmacokinetic study of 41 premature neonates (gestational age 29 +/- 3.2 weeks) during the first week of life demonstrated no imipenem accumulation after doses of 10 to 25 mg/kg/dose IV every 12 hours; however, significant accumulation of cilastatin occurred. The mean imipenem half-life was 2.5 hours, but the mean cilastatin half-life was 9.1 hours. The clinical significance of cilastatin accumulation in this population is not known.