Penbutolol

**Semantic type:** Pharmacologic Substance

**Definition:** A lipophilic, nonselective beta-adrenergic receptor antagonist with anti-anginal and antihypertensive activities. Penbutolol competitively binds to and blocks beta-1 adrenergic receptors in the heart, thereby decreasing cardiac contractility and rate. This leads to a reduction in cardiac output and lowers blood pressure. In addition, penbutolol prevents the release of renin, a hormone secreted by the kidneys that causes constriction of blood vessels.

**Synonyms:** - PENBUTOLOL