Drug Interactions between amoxicillin / clarithromycin / vonoprazan and thalidomide

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.

Although some in vitro data indicate synergism between macrolide antibiotics and penicillins, other in vitro data indicate antagonism. When these drugs are given together, neither has predictable therapeutic efficacy. Data are available for erythromycin, although theoretically this interaction could occur with any macrolide. Except for monitoring of the effectiveness of antibiotic therapy, no special precautions appear to be necessary.