Antibiotic
PREGNANCY RECOMMENDATION: No Human Data—Probably Compatible
BREASTFEEDING RECOMMENDATION: Limited Human Data—Probably Compatible
PREGNANCY SUMMARY
No reports describing the use of ertapenem in human pregnancy have been located. No teratogenicity was observed in two animal species, although mild fetal toxicity was observed in one at a dose very close to that used in humans. Moreover, there is no evidence that any beta-lactam antibiotic (e.g., penicillins and cephalosporins) causes developmental toxicity in humans at therapeutic doses. Therefore, if the maternal condition requires the use of ertapenem, the antibiotic probably is safe at any time during gestation.
FETAL RISK SUMMARY
Ertapenem is a broad-spectrum carbapenem antibiotic that is administered by either IM injection or IV infusion. It is structurally related to the beta-lactam antibiotics and belongs to the same class as imipenem (available as imipenem-cilastatin) and meropenem.
Reproduction studies have been conducted in mice and rats. No evidence of structural teratogenicity was observed at IV doses up to three times the recommended human dose of 1 g based on BSA (mice) and 1.2 times the human exposure at the recommended dose of 1 g based on AUC (rats) (1). However, the maximum dose in mice resulted in decreased fetal weight and decreases in the average number of ossified sacrocaudal vertebrae. The antibiotic had no effect on mating performance, fecundity, fertility, or embryonic survival in either species (1).
Ertapenem crosses the placenta in rats, but this has not been studied in humans. The molecular weight (about 498) is low enough that passage to the fetus should be expected.
BREASTFEEDING SUMMARY
Ertapenem is excreted into breast milk (1). Five women 5–14 days postpartum were treated with 1 g IV daily for 3–10 days. Milk concentrations of the antibiotic were measured at random times for 5 consecutive days after the last dose. Samples obtained within 24 hours of the last dose ranged from <0.13 (lower limit of quantitation) to 0.38 mcg/mL. By day 5, ertapenem could not be detected in the milk of four women and was <0.13 mcg/mL in one woman (1).
The effects on a nursing infant from exposure to ertapenem via milk are unknown but are of doubtful clinical significance. Most antibiotics are excreted into breast milk in low concentrations, and adverse effects are rare. Potential problems for the nursing infant are modification of bowel flora, direct effects on the infant (e.g., allergic response), and interference with the interpretation of culture results if a fever workup is required.
Reference
1.Product information. Invanz. Merck & Company, 2003.