Ketoconazole, is an antifungal 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 only recommended for severe infections when other agents cannot be used. Other uses include in the treatment of excessive hair growth 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 effect when taken by mouth include QT prolongation, adrenocortical insufficiency, and anaphylaxis. It is an imidazole and works by affecting the production of ergosterol required for the fungal cell membrane thereby slowing growth.
Ketoconazole was patented in 1977 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 2017, it was the 219th most commonly prescribed medication in the United States, with more than two million 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 The formulation that is taken by mouth was withdrawn in the European Union and in Australia in 2013 and in China in 2015.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.