US FDA warns high-dose of Pfizer's Diflucan during pregnancy may cause birth defects

The US Food and Drug Administration has warned that treatment with chronic, high doses (400-800mg/day) of drug behemoth Pfizer’s (NYSE: PFE) Diflucan (fluconazole) during the first trimester of pregnancy may be associated with a rare and distinct set of birth defects in infants.

This risk does not appear to be associated with a single, low dose of fluconazole 150mg to treat vaginal yeast infection (candidiasis). Based on this information, the pregnancy category for fluconazole indications (other than vaginal candidiasis) has been changed from category C to category D. The pregnancy category for a single, low dose of fluconazole has not changed and remains category C.

Diflucan is used to treat yeast infections of the vagina, mouth, throat, esophagus and other organs. It is also used to prevent yeast infections in patients who are likely to become infected because they are being treated with chemotherapy or radiation therapy before bone marrow transplant. The drug is also used to treat meningitis caused by a certain type of fungus. Pregnancy category D means there is positive evidence of human fetal risk based on human data but the potential benefits from use of the drug in pregnant women with serious or life-threatening conditions may be acceptable despite its risks.