Main Entry: be·ta–block·er

Pronunciation: \-ˈbläk-ər\

Function: noun

: any of a group of drugs (as propranolol) that combine with and block the activity of a beta-receptor to decrease the heart rate and force of contractions and lower high blood pressure and that are used especially to treat hypertension, angina pectoris, and ventricular and supraventricular arrhythmias—compare alpha-blocker