Ketoconazole

Ketoconazole is an imidazole antifungal agent used in the prevention and treatment of a variety of fungal infections. It functions by preventing the synthesis of ergosterol, the fungal equivalent of cholesterol, thereby increasing membrane fluidity and preventing growth of the fungus. Ketoconazole was first approved in an oral formulation for systemic use by the FDA in 1981. At this time it was considered a significant improvement over previous antifungals, miconazole and clotrimazole, due to its broad spectrum and good absorption. However, it was discovered that ketoconazole produces frequent gastrointestinal side effects and dose-related hepatitis. These effects combined with waning efficacy led to its eventual replacement by triazole agents, fluconazole, itraconazole, voriconazole, and posaconazole. Ketoconazole and its predecessor clotrimazole continue to be used in topical formulations.