Fluconazole is an antifungal medication used for a number of fungal infections. This includes candidiasis, blastomycosis, coccidioidomycosis, cryptococcosis, histoplasmosis, dermatophytosis, and tinea versicolor. It is also used to prevent candidiasis in those who are at high risk such as following organ transplantation, low birth weight babies, and those with low blood neutrophil counts. It is given either by mouth or by injection into a vein.

Common side effects include vomiting, diarrhea, rash, and increased liver enzymes. Serious side effects may include liver problems, QT prolongation, and seizures. During pregnancy it may increase the risk of miscarriage while large doses may cause birth defects. Fluconazole is in the azole antifungal family of medication. It is believed to work by affecting the fungal cellular membrane.

Fluconazole was patented in 1981 and came into commercial use in 1988. It is on the World Health Organization's List of Essential Medicines. Fluconazole is available as a generic medication. In 2021, it was the 165th most commonly prescribed medication in the United States, with more than 3 million prescriptions.

Medical uses

Fluconazole is a first-generation triazole antifungal medication. It differs from earlier azole antifungals (such as ketoconazole) in that its structure contains a triazole ring instead of an imidazole ring. While the imidazole antifungals are mainly used topically, fluconazole and certain other triazole antifungals are preferred when systemic treatment is required because of their improved safety and predictable absorption when administered orally.

Fluconazole's spectrum of activity includes most Candida species (but not Candida krusei or Candida glabrata), Cryptococcus neoformans, some dimorphic fungi, and dermatophytes, among others. Common uses include:

 • The treatment of non-systemic Candida infections of the vagina ("yeast infections"), throat, and mouth.

 • Certain systemic Candida infections in people with healthy immune systems, including infections of the bloodstream, kidney, or joints. Other antifungals are usually preferred when the infection is in the heart or central nervous system, and for the treatment of active infections in people with weak immune systems.

 • The prevention of Candida infections in people with weak immune systems, such as those neutropenic due to cancer chemotherapy, those with advanced HIV infections, transplant patients, and premature infants.

 •  As a second-line agent for the treatment of cryptococcal meningoencephalitis, a fungal infection of the central nervous system.

Side effects

Adverse drug reactions associated with fluconazole therapy include:

 • Common (≥1% of patients): rash, headache, dizziness, nausea, vomiting, abdominal pain, diarrhea, and/or elevated liver enzymes

 • Infrequent (0.1–1% of patients): anorexia, fatigue, constipation

 • Rare (<0.1% of patients): oliguria, hypokalaemia, paraesthesia, seizures, alopecia, Stevens–Johnson syndrome, thrombocytopenia, other blood dyscrasias, serious hepatotoxicity including liver failure, anaphylactic/anaphylactoid reactions

 • Very rare: prolonged , torsades de pointes

 • In 2011, the US FDA reports that treatment with chronic, high doses of fluconazole during the first trimester of pregnancy may be associated with a rare and distinct set of birth defects in infants.