Drug Interaction Report

GENERALLY AVOID: Coadministration with potent inhibitors of CYP450 3A4 may significantly increase the plasma concentrations of eletriptan, which is primarily metabolized by the isoenzyme. According to the product labeling, eletriptan peak plasma concentration (Cmax) and systemic exposure (AUC) increased by nearly 3-fold and 6-fold, respectively, during coadministration with ketoconazole (400 mg). The half-life increased from 5 hours to 8 hours. Likewise, erythromycin (1000 mg) increased eletriptan Cmax by 2-fold and AUC by nearly 4-fold, while half-life increased from about 5 hours to 7 hours. Clinically, this interaction may result in increased risk of vasospastic reactions associated with the use of 5-HT1 receptor agonists, such as coronary artery vasospasm, peripheral vascular ischemia, and colonic ischemia.

MANAGEMENT: Eletriptan should not be used within at least 72 hours of treatment with potent CYP450 3A4 inhibitors. Alternatively, other 5-HT1 receptor agonists that are not metabolized by CYP450 3A4 may be considered, such as frovatriptan, naratriptan, rizatriptan, sumatriptan, and zolmitriptan.

ADJUST DOSING INTERVAL: Food significantly enhances the oral bioavailability of boceprevir. When given at 800 mg three times daily with food, boceprevir exposure increased by up to 65% relative to administration in the fasting state. The bioavailability of boceprevir was similar regardless of meal type (e.g., high-fat versus low-fat) or whether taken 5 minutes prior to eating, during a meal, or immediately following completion of the meal. Therefore, boceprevir may be taken without regard to either meal type or timing of the meal.

MANAGEMENT: To ensure maximal oral absorption, boceprevir should be administered with a meal or light snack.