NCIt definition : The sulfate salt form of penbutolol, 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, bisoprolol prevents the release of renin, a hormone secreted
by the kidneys that causes constriction of blood vessels.;