Drug Interaction Report

Coadministration with inhibitors of CYP450 3A4 and/or P-glycoprotein may increase the systemic exposure to indacaterol following oral inhalation, as it is a substrate of both the isoenzyme and efflux transporter. When a single 300 mcg dose of indacaterol inhalation powder was administered in combination with the potent dual CYP450 3A4/P-glycoprotein inhibitor, ketoconazole (200 mcg twice daily for 7 days), indacaterol peak plasma concentration (Cmax) and systemic exposure (AUC) increased by 1.3- and 1.9-fold, respectively. These changes probably reflect the impact of maximal combined inhibition. Similarly, verapamil 80 mg three times a day for 4 days increased indacaterol Cmax by 1.5-fold and AUC by 2-fold, while erythromycin 400 mg four times a day for 7 days increased indacaterol Cmax by 1.2-fold and AUC by 1.4-fold. Ritonavir 300 mg twice daily for 7.5 days had no effect on the Cmax of indacaterol, but increased its AUC by 1.7-fold. Indacaterol oral inhalation powder has been evaluated in clinical trials for up to one year at doses up to 600 mcg. No dosage adjustment is necessary at the 75 mcg dose when used with CYP450 3A4 and P-glycoprotein inhibitors.

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.

GENERALLY AVOID: Use of anticholinergic agents with alcohol may result in sufficient impairment of attention so as to render driving and operating machinery more hazardous. In addition, the potential for abuse may be increased with the combination. The mechanism of interaction is not established but may involve additive depressant effects on the central nervous system. No effect of oral propantheline or atropine on blood alcohol levels was observed in healthy volunteers when administered before ingestion of a standard ethanol load. However, one study found impairment of attention in subjects given atropine 0.5 mg or glycopyrrolate 1 mg in combination with alcohol.

MANAGEMENT: Alcohol should generally be avoided during therapy with anticholinergic agents. Patients should be counseled to avoid activities requiring mental alertness until they know how these agents affect them.