Noun | 1. | metoprolol - beta blocker (trade name Lopressor) used in treating hypertension and angina and arrhythmia and acute myocardial infarction; has adverse side effects (depression and exacerbation of congestive heart failure etc.) beta blocker, beta-adrenergic blocker, beta-adrenergic blocking agent, beta-blocking agent - any of various drugs used in treating hypertension or arrhythmia; decreases force and rate of heart contractions by blocking beta-adrenergic receptors of the autonomic nervous system |