Ketoconazole

Clinical dataPronunciationTrade namesNizoral, othersOther namesR-41400; KW-1414AHFS/Drugs.comMonographMedlinePlusa682816License dataPregnancy
categoryRoutes of
administrationBy mouth (tablets), topical (cream, shampoo, solution)ATC codeLegal statusLegal statusPharmacokinetic dataBioavailabilityBy mouth: 37–97%Protein binding84 to 99%MetabolismExtensive liver (predominantly oxidation, O-dealkylation)MetabolitesN-deacetyl ketoconazoleElimination half-lifeBiphasicExcretionBile duct (major) and kidneyIdentifiersCAS NumberPubChemCIDIUPHAR/BPSDrugBankChemSpiderUNIIKEGGChEBIChEMBLPDB ligandCompTox Dashboard(EPA)ECHA InfoCard100.059.680Chemical and physical dataFormulaC₂₆H₂₈Cl₂N₄O₄Molar mass531.43 g·mol3D model (JSmol)ChiralityRacemic mixture(verify)

Ketoconazole, sold under the brand name Nizoral, among others, is an antiandrogen, antifungal, and antiglucocorticoid medication used to treat a number of fungal infections. Applied to the skin it is used for fungal skin infections such as tinea, cutaneous candidiasis, pityriasis versicolor, dandruff, and seborrheic dermatitis. Taken by mouth it is a less preferred option and recommended for only severe infections when other agents cannot be used. Other uses include treatment of excessive male-patterned hair growth in women and Cushing's syndrome.

Common side effects when applied to the skin include redness. Common side effects when taken by mouth include nausea, headache, and liver problems. Liver problems may result in death or the need for a liver transplantation. Other severe side effects when taken orally include QT prolongation, adrenocortical insufficiency, and anaphylaxis. It is an imidazole and works by hindering the production of ergosterol required for the fungal cell membrane, thereby slowing growth.

Ketoconazole was patented in 1977 by Belgian pharmaceutical company Janssen, and came into medical use in 1981. It is available as a generic medication and formulations that are applied to the skin are over the counter in the United Kingdom. In 2023, it was the 140th most commonly prescribed medication in the United States, with more than 3million prescriptions. The formulation that is taken by mouth was withdrawn in the European Union and in Australia in 2013, and in China in 2015. In addition, its use was restricted in the United States and Canada in 2013.