alpha blocker

views updated

alpha blocker (alpha-adrenergic blocker) n. a drug that prevents the stimulation of alpha-adrenergic receptors at the nerve endings of the sympathetic nervous system by noradrenaline and adrenaline: it therefore relaxes smooth muscle, causing (among other effects) widening of arteries (vasodilatation) and a drop in blood pressure. Alpha blockers include alfuzosin, doxazosin, phentolamine, phenoxybenzamine, indoramin, prazosin, and tamsulosin.