Drug Interaction Report

Moricizine may increase the plasma clearance of theophylline by 46% to 68% and decrease theophylline half-life by 20% to 34%. Decreased plasma theophylline levels may result. Conversely, theophylline toxicity may occur when moricizine is discontinued. The mechanism is unknown, but may be related to hepatic enzyme induction. Management consists of monitoring the patient for theophylline efficacy, checking levels if indicated, and adjusting theophylline dosage accordingly. Patients should be advised to notify their physician if they experience a worsening of their respiratory symptoms.

MONITOR: Coadministration of two or more sympathomimetic agents may increase the risk of adverse effects such as nervousness, irritability, and increased heart rate. Central nervous system (CNS) stimulants, particularly amphetamines, can potentiate the adrenergic response to vasopressors and other sympathomimetic agents. Additive increases in blood pressure and heart rate may occur due to enhanced peripheral sympathetic activity.

MANAGEMENT: Caution is advised if two or more sympathomimetic agents are coadministered. Pulse and blood pressure should be closely monitored.