Adults

For vaginal candidiasis: 150 mg as a single oral dose. For other indications, dosages vary from 50 mg to 400 mg daily, depending on the infection.

Elderly

No dosage adjustment typically required unless renal function is impaired. Dosage should be adjusted based on creatinine clearance.

Renal_impairment

Initial loading dose of 50-400 mg. Subsequent doses should be reduced by 50% for creatinine clearance < 50 mL/min (e.g., half the usual daily dose).

Onset

Antifungal effects typically begin within hours of administration.

Excretion

Primarily excreted unchanged in the urine, accounting for approximately 80% of the administered dose.

Half life

Approximately 30 hours, allowing for once-daily dosing for many indications.

Absorption

Well absorbed orally, with bioavailability typically exceeding 90%. Peak plasma concentrations are achieved within 1-2 hours.

Metabolism

Minimally metabolized; approximately 11% of the dose is metabolized to less active metabolites.

Warfarin

Increased prothrombin time; monitor INR.

Phenytoin

Increased plasma phenytoin concentrations; monitor phenytoin levels.

Rifampicin

Decreased fluconazole plasma concentrations.

Cyclosporine

Increased plasma cyclosporine concentrations.

Sulfonylureas

Increased plasma concentrations of sulfonylureas; monitor blood glucose.

Hydrochlorothiazide

Increased fluconazole plasma concentrations.

Oral contraceptives

May alter levels of estrogen and progestin.