Ketoconazole, prescription drug used to treat fungal infections. It works by weakening fungal cell walls, thereby either killing the fungus or stopping its growth. Ketoconazole is also used to treat prostate cancer because it suppresses the production of testosterone, a hormone necessary for prostate cancer cell survival.
Ketoconazole is available as a tablet, cream, or shampoo. Patients using the drug in tablet form take 200 to 400 mg once a day for fungal infections and 400 mg three times a day for prostate cancer. The drug should be taken with food for better absorption and to avoid stomach irritation. It must be taken for two to four weeks before a physician can evaluate its effectiveness as an antifungal agent. A cure may require many months of treatment.
Common side effects of ketoconazole include reduced testosterone production (which may impair sexual function in males), skin irritation and rash, headache, nausea, diarrhea, and liver problems. Pregnant and nursing women, patients with active liver disease, and patients who have previously had an allergic reaction to the drug should not take ketoconazole. Patients should exercise caution in taking the drug if they are allergic to related antifungal drugs, take any other drugs, have liver disease or reduced liver function, have a history of alcoholism, or have low levels of hydrochloric acid in their stomachs.
Ketoconazole enhances the blood-thinning effects of warfarin and minimizes the effects of theophylline. Antacids may lessen ketoconazole’s effectiveness. Patients who consume alcohol while taking this drug may experience dizziness, headaches, and nausea. Alcohol in combination with ketoconazole can also contribute to liver problems.