Diflucan (fluconazole) is a potent systemic antifungal, and has been used in nursing mothers to treat candidiasis of the breast. Fluconazole is transferred in minimal quantities into mother's milk. (It has a low milk:plasma ratio of .46 to .85.) Fluconazole peaks in your bloodstream approximately one to two hours after administration, but, with an adult half-life of 30 hours, it remains in your system for quite some time (Hale 1997).

"Two references have reported the safe use of this antifungal agent in neonates ... The safety of fluconazole during breastfeeding cannot be completely extrapolated from these cases, but the dose administered to these infants far exceeds the amount they would have received via breastmilk ... fluconazole is probably safe to use during breastfeeding" (Briggs, Freeman & Yaffe, 1994).

When dosing, it is always wise to avoid the time a medication peaks in your bloodstream, as this corresponds to the time it also peaks in your milk.