Ornidazole is not approved for marketing in the United States by the U.S. Food and Drug Administration, but is available in other countries. The amount of ornidazole in milk is low after administration of 3 doses totaling 2 grams intravenously perinatally. Measurements of infant plasma levels during breastfeeding have not been reported. No studies have evaluated adverse effects of ornidazole on the infant during breastfeeding, but presumably they are similar to those of the closely related drug, metronidazole, such as increased risk of oral and rectal Candida infections.
As with metronidazole, concern has been raised about exposure of healthy infants to ornidazole via breastmilk,[1] because of possible mutagenicity and carcinogenicity. Opinions vary among experts on the advisability of using ornidazole during longer-term therapy while breastfeeding, but avoidance of breastfeeding for 3 days after a single dose should allow milk levels to drop to negligible values because its half-life is similar to tinidazole.[2] Other drugs are available for bacterial vaginosis, and can be given vaginally, which should result in lower amounts in breastmilk.