Flucytosine
Risk Factor: CM
Class: ANTI-INFECTIVES
/ Antifungals
Contents of this page:
Fetal Risk Summary
Breast Feeding Summary
References
Questions and Answers
Fetal Risk Summary
The antifungal agent, flucytosine, was teratogenic in rats at doses 0.27 to 4.7 times the maximum recommended human dose (MRHD), producing vertebral fusions, cleft lip and palate, and micrognathia (1). In mice, a dose 2.7 times the MRHD was associated with a low, nonsignificant, incidence of cleft palate. Flucytosine was not teratogenic in rabbits at 0.68 times the MRHD (1).
Following oral administration, about 4% of the drug is metabolized within the fungal organisms to 5-fluorouracil, an antineoplastic agent (1, 2). Fluorouracil is suspected of producing congenital defects in humans (see Fluorouracil).
Three case reports of pregnant patients treated in the 2nd and 3rd trimesters with flucytosine have been located (3,4 and 5). No defects were observed in the newborns.
Breast Feeding Summary
No reports describing the use of flucytosine during lactation or measuring the amount, if any, excreted in human milk have been located. Because of the potential for serious adverse effects in a nursing infant, breast feeding while taking flucytosine is not recommended.
References
- Product information. Ancobon. ICN Pharmaceuticals, 2000.
- Diasio RB, Lakings DE, Bennett JE. Evidence for conversion of 5-fluorocytosine to 5-fluorouracil in humans: possible factor in 5-fluorocytosine clinical toxicity. Antimicrob Agents Chemother 1978;14:9038.
- Philpot CR, Lo D. Cryptococcal meningitis in pregnancy. Med J Aust 1972;2:10057.
- Schonebeck J, Segerbrand E. Candida albicans septicaemia during first half of pregnancy successfully treated with 5-fluorocytosine. Br Med J 1973;4:3378.
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Curole DN. Cryptococcal meningitis in pregnancy. J Reprod Med 1981;26:3179.
