Drug Interaction Report

MONITOR: Thalidomide can cause bradycardia and may have additive effects with other drugs that decrease heart rate. Cases of bradycardia have been associated with thalidomide use, some requiring medical interventions. The clinical significance and underlying etiology of the bradycardia observed with thalidomide treatment have not been established. However, the potential for additive bradycardic effects should be considered when used with other drugs that slow cardiac conduction such as beta-blockers, calcium channel blockers, digitalis, flecainide, moricizine, and propafenone. Non-cardiac drugs that may also cause bradycardia include atazanavir, lacosamide, lithium, mefloquine, succinylcholine, H2-receptor antagonists, tricyclic antidepressants, and anticholinesterase or cholinergic agents. Because bradycardia is a risk factor for torsade de pointes arrhythmia, concerns also exist when thalidomide is used with drugs that prolong the QT interval or cause torsade de pointes.

MANAGEMENT: Caution is advised when thalidomide is used with drugs that can slow the heart rate or induce torsade de pointes arrhythmia. Patients should be monitored for bradycardia, atrioventricular block and syncope, and advised to seek medical attention if they experience dizziness, lightheadedness, fainting, shortness of breath, or slow or irregular heartbeat. A dose reduction of thalidomide or discontinuation may be required.

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.