Dirithromycin
Risk Factor: CM
Class: ANTI-INFECTIVES
/ Antibiotics/Anti-infectives
Contents of this page:
Fetal Risk Summary
Breast Feeding Summary
References
Questions and Answers
Fetal Risk Summary
Dirithromycin, a semisynthetic antibiotic structurally related to erythromycin, belongs to the same macrolide class of antiinfectives as azithromycin, clarithromycin, erythromycin, and troleandomycin (the triacetyl ester of oleandomycin). Dirithromycin is a prodrug that is converted by nonenzymatic hydrolysis in the intestinal tract to the active form of the antibiotic, erythromycylamine.
No teratogenic effects were observed in the offspring of pregnant mice dosed with 1000 mg/kg (8 times the recommended maximum human dose on a mg/m2 basis [MRHD]) (1). A significant increase in the incidence of fetal growth retardation was observed at this dose, as well as an increased occurrence of incomplete ossification (a result of retarded development). Doses up to 21 and 4 times the MRHD in rats and rabbits, respectively, revealed no evidence of impaired fertility or fetal harm (1).
No reports describing the use of dirithromycin in human pregnancy have been located. The antibiotic was approved in 1995 by the FDA for use in the United States.
Breast Feeding Summary
No reports describing the use dirithromycin during breast feeding or measuring the amount of drug in milk have been located. The antibiotic is excreted into the milk of rodents (1). Because other antibiotics in this class appear in milk (e.g., see Erythromycin), the passage of dirithromycin into human milk should be expected. Based on experience with other antibiotics, including erythromycin, the risk to a nursing infant from dirithromycin in breast milk are probably minimal, but, because this is a new drug, caution should be exercised until the effects, if any, of this exposure have been studied.
References
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Product information. Dynabac. Sanofi Pharmaceuticals, 2000.
