Drug Interaction Report

MONITOR: Coadministration with inhibitors of CYP450 2D6 and/or 3A4 may increase the plasma concentrations of cevimeline, which is metabolized by these isoenzymes.

MANAGEMENT: Dosage adjustments and clinical monitoring may be appropriate whenever a CYP450 2D6 and/or 3A4 inhibitor is added to or withdrawn from therapy. Patients should be advised to notify their physician if they experience excessive adverse cholinergic effects of cevimeline such as nausea, vomiting, diarrhea, sweating, salivation, urinary frequency, visual disturbance, confusion, tremor, palpitations, or irregular heartbeat.

ADJUST DOSING INTERVAL: Food may reduce the oral absorption and bioavailability of zafirlukast. In two separate studies, one using a high-fat and the other a high-protein meal, administration of zafirlukast with food reduced the mean bioavailability by approximately 40%.

MANAGEMENT: To ensure maximal oral absorption, zafirlukast should be administered at least 1 hour before or 2 hours after meals.