Diflucan and BCPs

[queenjulie, RN]

A friend is taking Diflucan for a yeast infection, and her doctor warned her that it can interfere with her birth control pills. Is that true? I checked several drug references and didn't find anything to indicate that. Does anyone have experience with Diflucan and BCPs?

[RNTOBE_1970]

From the PDR>>>See Contraindications. Severe hypoglycemia with oral hypoglycemics. May increase PT with coumarin-type drugs (eg, warfarin). Increases levels of phenytoin, cyclosporine, zidovudine, rifabutin, tacrolimus, terfenadine, cisapride, glipizide, glyburide, tolbutamide, theophylline, astemizole, and other drugs metabolized by the CYP450 system. Rifampin enhances metabolism of fluconazole. Increases levels and psychomotor effects of midazolam; consider dose reduction of short-acting benzodiazepines. Decreased levels with cimetidine. Increased levels with HCTZ. May increase levels of ethinyl estradiol-, levonorgestrel-, and norethindrone-containing oral contraceptives. Greater incidence of abnormally elevated serum transaminases with one or more of the following medications: rifampin, phenytoin, isoniazid, valproic acid, or oral sulfonylureas. Uveitis reported with rifabutin. Nephrotoxicity reported with tacrolimus. Cardiac events reported with cisapride.

[nikkeylane]

I've used Diflucan for patients in private practice all the time. Your friend shouldn't have a problem. Generally the medication is taken once. If the infection is bad it might be taken once a week for 2 weeks. So the maximum she should take is 2 pills total.

[Frozen08]

flucanazole works by inhibiting fungal P450 enzyme systems to decrease the production of ergosterol, a component of fungal membranes.

There is some cross reactivity between the fungal and our P450 inhibition, which as the PDR poster pointed out can increase the dosage of other drugs.

BCP happen to be metabolized by the same P450 isozyme that fluc works to inhibit.