Ketoconazole is categorized under the drug class of azole antifungals and is used in the treatment of a series of severe fungal infections on an individual. This medication is adopted as an option when other anti-fungal infections have failed with a patient or have given adverse side effects. Ketoconazole is a synthetic imidazole antifungal medication that is exclusively used to treat fungal infections. Care should, however, be taken not to apply the drug on toenails or fingernails. The drug is sold as a commercial tablet for oral administration. The brand names of the drugs include Extina, Nizoral, and Xolegel. Ketoconazole is used in the treatment of fungal infections. The prescription of the drug comes as shampoo and cream for application to the skin. The cream is applied once daily for 2 to 6 weeks. The shampoo is applied once on the scalp to treat the infection and can be applied for between 3 to 4 days for up to 8 weeks. It is advisable to stick to the directions of use on the label of the drug. Consult your doctor about any direction that is not clear. The drug performs by preventing fungi from producing ergosterol, a substance that forms part of the fungal cell membranes and responsible for the spread of infections.