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Review

Metronidazole

No authors listed
In: Drugs and Lactation Database (LactMed®) [Internet]. Bethesda (MD): National Institute of Child Health and Human Development; 2006.
.
Free Books & Documents
Review

Metronidazole

No authors listed.
Free Books & Documents

Excerpt

With maternal intravenous and oral therapy, breastfed infants receive metronidazole in doses that are less than those used to treat infections in infants, although the active metabolite adds to the total infant exposure. Plasma levels of the drug and metabolite are measurable, but less than maternal plasma levels. Case reports of Candida infections and diarrhea have been reported, and a comparative trial suggested that oral and rectal colonization with Candida might be more common in infants exposed to metronidazole.

Neither topical nor vaginal metronidazole have been studied during breastfeeding. After vaginal administration, plasma levels are less than 2% of those after a 500 mg oral dose. After topical administration, blood levels are about 1% of the peak plasma levels after a 250 mg oral dose. Only water-miscible cream or gel products should be applied to the breast because ointments may expose the infant to high levels of mineral paraffins via licking.[1]

Because of the well demonstrated genotoxicity and mutagenicity in bacteria, carcinogenicity in animals, and possible mutagenicity in humans,[2,3] concern has been raised about exposure of healthy infants to metronidazole via breastmilk. The relevance of these findings has been questioned and no definitive study has yet been performed in humans.

Opinions vary among experts on the advisability of using metronidazole during longer-term therapy while breastfeeding, but some sources recommend discontinuing breastfeeding for 12 to 24 hours after a single dose of 2 grams, but not after lower dosages.[4] Other drugs are available for some conditions that metronidazole is used to treat. Topical or vaginal use of metronidazole during breastfeeding is unlikely to be of concern, although the manufacturer of one vaginal product recommends not breastfeeding during treatment and for 2 days after the last dose.

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References

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    1. Gray MS, Kane PO, Squires S. Further observations on metronidazole (Flagyl). Br J Vener Dis 1961;37:278-9. - PMC - PubMed

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