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 causes widening of arteries (vasodilatation) and a drop in blood pressure. Alpha blockers include doxazosin, phentolamine, phenoxybenzamine, moxisylyte, indoramin, prazosin, alfuzosin, and tamsulosin. Overdosage causes a severe drop in blood pressure, a rapid pulse, nausea and vomiting, diarrhoea, a dry mouth, flushed skin, convulsions, drowsiness, and coma.
Medical dictionary. 2011.