Drug Interaction Report

Consumer information for this interaction is not currently available.

GENERALLY AVOID: Coadministration with potent inducers of CYP450 3A4 may significantly decrease the oral bioavailability and plasma concentrations of itraconazole and ketoconazole. In vitro studies have shown that CYP450 3A4 is the major enzyme involved in their metabolism, and pharmacokinetic studies as well as case reports have demonstrated decreases in itraconazole and ketoconazole systemic exposure (AUC) by at least 80% and sometimes even to undetectable levels when coadministered with potent CYP450 3A4 inducers such as rifampin or phenytoin, including reports of treatment failure.

MANAGEMENT: Concomitant use of itraconazole or ketoconazole with potent CYP450 3A4 inducers should generally be avoided. Some authorities recommend avoiding coadministration of potent CYP450 3A4 inducers from 2 weeks before and during treatment with these azole antifungal agents unless the benefits outweigh the risk of potentially reduced antifungal efficacy. If coadministration is required, clinical response and antifungal activity should be closely monitored and the itraconazole or ketoconazole dosage increased as necessary.

Food increases the absorption of itraconazole capsules but decreases the absorption of itraconazole oral solution. Capsules should be taken immediately after a full meal and the solution be taken on an empty stomach to ensure best results.

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