Medical Author: Omudhome Ogbru, Pharm.D.
Medical Editor: Jay Marks, M.D.

GENERIC NAME: ketoconazole

BRAND NAME: Nizoral, Extina, Xolegel, Kuric

DRUG CLASS AND MECHANISM: Ketoconazole is an anti-fungal medication in the same family of drugs as fluconazole (Diflucan), itraconazole (Sporanox), and miconazole (Micatin, Monistat). It prevents growth of several types of fungi by preventing production of the membranes that surround fungal cells. The FDA approved ketoconazole in June 1981.

PRESCRIPTION: Yes

GENERIC AVAILABLE: Yes

PREPARATIONS: Tablets: 200 mg; Shampoo: 1 and 2%; Cream: 2%, Gel: 2%, Foam: 2%

STORAGE: Tablets should be stored at room temperature, 15-25 C (59-77 F) and protected from moisture.

• Store shampoo 1% between 2-30 C (35-86 F) and protect it from light and freezing.
• Store shampoo 2% at or below 25 C (77 F) and protect it from light.
• Store cream and foam at room temperature, 20-25 C (68-77 F).
• Store gel between 15-30 C (59- 86 F).

PRESCRIBED FOR: Oral ketoconazole treats a variety of fungal infections such as candidiasis of the skin or mouth (thrush), blastomycosis, histoplasmosis, coccidiomycosis, and others. Ketoconazole is also used to treat fungal infections that have not responded to griseofulvin, another antifungal medication. Topical ketoconazole is used for treating ringworm, jock itch, athlete's foot, dandruff, and tinea versicolor.

DOSING: Ketoconazole may be taken with or without food. The oral dose range is 200-400 mg daily. Topical formulations are administered to affected areas once or twice daily.

DRUG INTERACTIONS: There are no known drug interactions with topical ketoconazole.

Ketoconazole tablets require stomach acidity to dissolve. Therefore, ketoconazole should be administered at least two hours before taking antacids or other acid reducing medications such as cimetidine (Tagamet) or ranitidine (Zantac). Combining ketoconazole with alcohol may cause a very unpleasant reaction (disulfiram reaction).

Rifampin (Rifadin, Rimactane, Rifamate, Rifater) reduces the blood concentration of oral ketoconazole, probably by increasing the elimination of fluconazole by the liver. This may reduce the effectiveness of ketoconazole.

Ketoconazole may increase the concentration of warfarin (Coumadin) in blood by reducing the elimination of warfarin. Therefore, the effect of warfarin may increase, leading to an increased tendency to bleed.

Ketoconazole also increases the concentration of phenytoin, (Dilantin) cyclosporine, zidovudine (Retrovir), theophylline (Theo-Dur, Respbid, Slo-Bid, Theo-24, Theolair, Uniphyl, Slo-Phyllin), tolbutamide, glyburide (Micronase, Diabeta, Glynase), glipizide (Glucotrol), protease inhibitors [for example, indinavir (Crixivan), ritonavir (Norvir), saquinavir (Invirase, Fortovase)], midazolam (Versed) and triazolam (Halcion). Increased drug concentrations usually increase the incidence of side effects.

Ketoconazole also may reduce the elimination of some "statins" [for example, simvastatin (Zocor)] leading to an increase in the blood levels of statins and increasing the risk of side effects such as rhabdomyolysis (severe muscle injury).

PREGNANCY: Ketoconazole has not been adequately studied in pregnant women.

NURSING MOTHERS: A small amount of ketoconazole is secreted in breast milk. Nursing mothers should probably avoid breastfeeding while using ketoconazole.

SIDE EFFECTS: Ketoconazole is generally well tolerated. Ketoconazole can cause rash, itching, nausea, vomiting, abdominal pain, headache, dizziness, fatigue, impotence, and blood count abnormalities. Rarely, ketoconazole has serious allergic reactions (anaphylaxis). Also rarely, ketoconazole has been associated with severe depression, hair loss, and tingling sensations. Liver dysfunction has also been reported. Signs of liver problems include unusual fatigue, loss of appetite, nausea and vomiting, yellowing of the skin (jaundice), dark urine, and pale stools. Development of these symptoms while taking ketoconazole should be reported to a physician.

Reference: FDA Prescribing Information