ketoconazole, Nizoral, Extina, Xolegel, Kuric (cont.)

Pharmacy Author:
Medical and Pharmacy Editor:

DOSING: Ketoconazole may be taken with or without food. The oral dose range is 200-400 mg daily. Recurrent tinea versicolor is treated with 400 mg monthly. 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 concentrations in the blood 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), triazolam (Halcion), and alprazolam (Xanax). Increased drug concentrations usually increase the incidence of side effects.

Medically Reviewed by a Doctor on 4/1/2013


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