Known brand names include Diflucan.
An antifungal tablet or liquid for yeast infections of the vagina, mouth, throat, and esophagus, and for cryptococcal meningitis, a fungal infection around the brain and spinal cord. It interacts with many other drugs and can rarely cause liver injury or a dangerous heart rhythm.
A single oral dose is a convenient option for uncomplicated vaginal candidiasis, though topical azoles work as well with fewer systemic effects. Fluconazole is preferred for many Candida albicans infections and for consolidation and maintenance therapy of cryptococcal meningitis after amphotericin B induction. It does not cover molds such as Aspergillus, C. krusei is resistant, and C. glabrata is often less susceptible, so an echinocandin or another agent is used there. It has fewer interactions than ketoconazole or itraconazole, but they are still significant.
A triazole antifungal that selectively inhibits fungal cytochrome P450-dependent lanosterol 14-alpha-demethylase, blocking conversion of lanosterol to ergosterol; the resulting loss of normal sterols and buildup of 14-alpha-methyl sterols is fungistatic. Oral bioavailability is over 90%, peak levels occur in 1 to 2 hours, and the half-life is about 30 hours (20 to 50). About 80% of a dose is excreted unchanged in urine, and CSF levels reach about 80% of plasma in fungal meningitis. It is a moderate CYP2C9 and CYP3A4 inhibitor and a strong CYP2C19 inhibitor, and inhibition persists 4 to 5 days after stopping.
The label does not describe a narrow therapeutic index or direct dosing by measured blood levels of the drug.
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Doses come from the FDA label. Study tool, not for clinical decisions.
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No change for single-dose vaginal candidiasis therapy. For multiple doses, give a 50 to 400 mg loading dose, then 100% of the usual dose if creatinine clearance is above 50 mL/min and 50% if 50 or less without dialysis. On hemodialysis, give 100% of the dose after each session.
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No dose table. Use with caution in liver dysfunction; serious and sometimes fatal hepatotoxicity has occurred, mostly in patients with serious underlying illness.
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No specific antidote. Overdose has caused hallucinations and paranoid behavior; give symptomatic and supportive care, with gastric lavage if indicated. A 3-hour hemodialysis session lowers plasma levels by about 50%.
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Avoid in pregnancy except for severe or life-threatening fungal infections where benefit outweighs risk. High doses (400 to 800 mg/day) through most or all of the first trimester have been linked to a distinct pattern of birth defects, and epidemiologic studies suggest possible miscarriage and birth defect risk even with 150 mg doses in the first trimester. Women who could become pregnant and take 400 to 800 mg/day should use effective contraception during treatment and for about 1 week after the last dose.
Low levels pass into breast milk after a single 150 mg dose; the estimated infant dose is about 13% of the pediatric oropharyngeal maintenance dose. There are no data after repeated or high doses, so use caution while breastfeeding.
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Oropharyngeal or esophageal candidiasis (6 months and older): 6 mg/kg on day 1, then 3 mg/kg once daily, up to 12 mg/kg/day for esophageal disease. Systemic Candida infections (3 months and older): 25 mg/kg on day 1 (maximum 800 mg), then 12 mg/kg daily (maximum 400 mg); infants under 3 months also get the 25 mg/kg load, then 12 mg/kg daily, or 9 mg/kg if born before 30 weeks' gestation. Cryptococcal meningitis: 12 mg/kg on day 1, then 6 mg/kg daily. Prophylaxis was not shown effective in premature infants under 750 grams, who had more intestinal perforation.