indication

For the treatment of hypertension, angina, and arrhythmia

pharmacology

Alprenolol is a non-selective beta-blocker used in the treatment of hypertension, edema, ventricular tachycardias, and atrial fibrillation. Alprenolol impairs AV node conduction and decreases sinus rate and may also increase plasma triglycerides and decrease HDL-cholesterol levels. Alprenolol is nonpolar and hydrophobic, with low to moderate lipid solubility. Alprenolol has little to no intrinsic sympathomimetic activity and, unlike some other beta-adrenergic blocking agents, alprenolol has little direct myocardial depressant activity and does not have an anesthetic-like membrane-stabilizing action.

mechanism of action

Alprenolol non-selectively blocks beta-1 adrenergic receptors mainly in the heart, inhibiting the effects of epinephrine and norepinephrine resulting in a decrease in heart rate and blood pressure. Also, with a more minor effect, by binding beta-2 receptors in the juxtaglomerular apparatus, alprenolol inhibits the production of renin, thereby inhibiting angiotensin II and aldosterone production and therefore inhibits the vasoconstriction and water retention due to angiotensin II and aldosterone, respectively.

toxicity

LD₅₀=597.0 mg/kg (Orally in rats)

biotransformation

Hepatic. One of the active metabolites, 4-OH-alprenolol, is an active beta-blocker.

half life

2-3 hours