Antibiotic
PREGNANCY RECOMMENDATION: No Human Data—Animal Data Suggest Low Risk
BREASTFEEDING RECOMMENDATION: No Human Data—Probably Compatible
PREGNANCY SUMMARY
No reports describing the use of fidaxomicin in human pregnancy have been located. The animal reproduction data suggest low risk. Because only minimal amounts (in the ng/mL range) of fidaxomicin are detected in the systemic circulation, the drug is probably compatible in pregnancy.
FETAL RISK SUMMARY
Fidaxomicin is an oral macrolide antibacterial agent. It is indicated in adults (≥18 years of age) for the treatment of Clostridium difficile–associated diarrhea. The drug is in the same macrolide antibacterial class as azithromycin, clarithromycin, dirithromycin, erythromycin, and troleandomycin. Fidaxomicin acts in the gastrointestinal tract. Systemic absorption is minimal with plasma concentrations in the ng/mL range. It is metabolized to an active metabolite (OP-1118) in the gut and both the parent drug and metabolite are excreted in the feces with elimination half-lives of 9 and 10 hours, respectively (1).
Reproduction studies have been conducted in rats and rabbits. In these species, IV doses producing plasma exposures that were about 200 and 66 times, respectively, the human exposure based on AUC (HE) revealed no evidence of fetal harm (1).
Long-term carcinogenicity studies have not been conducted with fidaxomicin. Neither the parent drug nor OP-1118 was mutagenic in two assays, but fidaxomicin was clastogenic in one test. No effects on fertility in male and female rats were observed with systemic exposures that were about 100 times the HE (1).
It is not known if fidaxomicin crosses the human placenta. Minimal concentrations of other macrolide antibacterials cross the placenta (e.g., azithromycin and erythromycin) and fidaxomicin might also cross. However, fidaxomicin plasma concentrations are minimal and any exposure of the embryo–fetus should be clinically insignificant.
BREASTFEEDING SUMMARY
No reports describing the use of fidaxomicin during human lactation have been located. Because plasma concentrations of the antibacterial are minimal (ng/mL range), adverse effects in a nursing infant are not expected.
Reference
1.Product information. Optimer Pharmaceuticals, 2011.