Prazosin-induced first-dose phenomenon possibly associated with hemorrhagic stroke: a report of three cases

A small initial dose of prazosin ranging from 0.5 to 1 mg has been recommended to avoid the first-dose phenomenon characterized by a sudden and severe drop in blood pressure after the administration of the first dose of prazosin. However, even with an initial dose of 0.5 mg, hypotension with consciousness disturbance developed in three hypertensive patients with recent cerebral hemorrhage. We present this report to alert physicians and pharmacists about the potential risk of the first-dose phenomenon even at the recommended initial doses of prazosin in hypertensive patients who have suffered a recent stroke.