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A Guide to the Clinical Care of Women with HIV/AIDS, 2005 edition

 

Table 14-5: Safety of Commonly Used Antimicrobials

Drug Name	FDA Class	Animal Data	Human Experience in Pregnancy	Comments
Metronidazole	B	Animal (rodents) data show risk of carcinogenicity.	2 meta-analyses, a population-based case-control study, and a prospective controlled cohort study have not found increased risk in birth defects (Diav-Citrin, 2001; Czeizel, 1998, Caro-Paton, 1997; Burtin 1995)	Most authorities feel metronidazole is safe in the 2nd and 3rd trimester. Use with caution in 1st trimester.
Clindamycin	B	No fetal harm demonstrated in rat studies. Cleft palate observed in one mouse strain.	In a surveillance study of Michigan Medicaid recipients, 647 exposures to clindamycin during the first trimester resulted in a 4.8% incidence of birth defects. Patterns of anomalies do not support an association between clindamycin and congenital effects (Briggs, 1998).	Clindamycin is usually considered safe to use during pregnancy.
Penicillins	B	Carcinogenicity demonstrated in rats after prolonged subcutaneous administration of penicillin in peanut oil.	Several collaborative perinatal project reports involving over 12,000 exposures to penicillin derivatives during the 1st trimester indicated no association between penicillin derivative drugs and birth defects (Briggs,1998).	Penicillins are usually considered safe to use during pregnancy.
Cephalosporins	B	Not teratogenic or fetotoxic.	Extensive pregnancy exposure was not associated with birth defects.	Cephalosporins are usually considered safe to use during pregnancy.
Erythromycin	B	No teratogenic effect in rat studies.	In a surveillance study of Michigan Medicaid recipients, 6972 patients exposed to erythromycin during the first trimester resulted in a 4.6% incidence of birth defects. Patterns of anomalies do not support an association between erythromycin and congenital malformations.	Avoid estolate salt (due to hepatotoxicity in 10% of patients). Other forms are usually considered safe to use during pregnancy.
Tetracyclines	D	Teratogenic in animal studies resulting in retardation of skeletal development and embryotoxicity.	Tetracyclines are contraindicated in pregnancy due to retardation of skeletal development and bone growth, enamel hypoplasia, and discoloration of teeth of fetus. Maternal liver toxicity has also been reported.	Contraindicated.
Fluoroquinolones	C	Animal data demonstrated arthropathy in immature animals resulting in erosions in joint cartilage.	In a prospective follow-up study conducted by the European Network of Teratology Information Services (ENTIS), 666 cases of fluoroquinolone exposure (the majority during the 1st trimester) showed a congenital malformation rate of 4.8%. From previous epidemiologic data, this rate did not exceed the background rate (Schaefer, 1996).	Based on animal data and the availability of alternative antimicrobial agents, the use of fluoroquinolones during pregnancy is contraindicated.
Aminoglycosides	D	Fetotoxicity reported in rodent studies.	Eighth cranial nerve toxicity in the fetus is well documented with exposure to kanamycin and streptomycin and can potentially occur with other aminoglycosides.	Gentamicin is classified by the FDA as “C” (although it has the same potential adverse effects). Use as preferred aminoglycoside if treatment indicated.
Imipenem	C	Animal studies (monkeys) show increased embryogenic loss	No data in humans.	Due to the lack of human data, use only in life-threatening infections.
Metropenem	B	No risk.	No data in humans.	Due to the lack of human data, use only in life-threatening infections.
Chloramphenicol	C	No animal data.	A collaborative perinatal project monitored 98 exposures during the first trimester and 348 exposures anytime during pregnancy. No relationship between chloramphenicol and malformations were found (Briggs, 1998).	Although apparently nontoxic to the fetus, chloramphenicol should not be used near term due to the potential of cardiovascular collapse (gray baby syndrome).
Aztreonam	B	Animal studies show no harm to the fetus.	No human data available.	Likely to be safe in pregnancy, but due to the lack of data, use only if absolutely needed.
Methenamine	C	No animal data.	In a surveillance study of Michigan Medicaid recipients, 209 exposures to methenamine during the first trimester resulted in a 3.8% incidence of birth defects. This data did not support an association between methenamine and congenital defects.	The benefit of methenamine therapy is not likely to be worth the potential risk of use during pregnancy.
Nitrofurantoin	B	Not teratogenic or fetotoxic in rat and rabbit studies.	In a surveillance study of Michigan Medicaid recipients, 1292 exposures to nitrofurantoin resulted in a 4.0% incidence of birth defects. These data did not support an association between nitrofurantoin and congenital defects (Briggs, 1998).	Most authorities feel that use of nitrofurantoin is safe during pregnancy.
Vancomycin	C	No animal data.	The manufacturer has received reports of vancomycin use during pregnancy without adverse fetal effects.	Consider use only when the benefit outweighs the risk of drug administration.