Adults

Dosage varies by indication. For tinea infections: 50 mg once daily for 2-4 weeks. For vaginal candidiasis: a single 150 mg dose (Note: 50 mg is not typically for single dose vaginal candidiasis, usually for maintenance or specific superficial infections). For systemic infections: initial 400 mg, then 200-400 mg daily. For cryptococcal meningitis: initial 400 mg, then 200-400 mg daily for 6-8 weeks.

Elderly

No dosage adjustment is typically required in elderly patients with normal renal function.

Renal_impairment

Dosage adjustment is necessary based on creatinine clearance (CrCl). For CrCl 21-50 mL/min, administer 50% of the usual daily dose. For CrCl ≤20 mL/min, administer 25% of the usual daily dose. Patients on hemodialysis should receive a full dose after each dialysis session.

Onset

Onset of action varies with infection type and severity. Clinical improvement typically seen within a few days.

Excretion

Primarily renal; approximately 80% of the administered dose is excreted unchanged in urine.

Half life

Approximately 30 hours, allowing for once-daily dosing.

Absorption

Well absorbed orally; bioavailability is >90%. Peak plasma concentrations are achieved within 0.5-1.5 hours.

Metabolism

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

Warfarin

Increased prothrombin time, monitor INR.

Phenytoin

Increased phenytoin levels, monitor levels.

Rifampicin

Decreased fluconazole levels, consider increasing fluconazole dose.

Cyclosporine

Increased cyclosporine levels, monitor levels.

Hydrochlorothiazide

Increased fluconazole plasma concentrations.

Oral contraceptives

Increased AUC of ethinyl estradiol and levonorgestrel.

Oral Hypoglycemics (sulfonylureas)

Increased risk of hypoglycemia, monitor blood glucose.

Statins (e.g., Atorvastatin, Simvastatin)

Increased risk of myopathy/rhabdomyolysis, use with caution.