Drug with a first dose effect:: (A) Yohimbine, (B) Verapamil, (C) Dopamine, (D) Prazosin
Answer is D. (Ref: Katzung, 14th ed. pg. 159)First dose effect is sudden severe hypotension while changing position from lying to a standing position after first dose intake of alpha blocker, ACE inhibitor.Most common class of drug for causing first dose effect: selective alpha-1 blockerSelective alpha-1 blocker Drugs:# Prazosin: Most common among all# Terazosin# Doxazosin# AlfuzosinOther drugs that can cause first dose effect is: Phentolamine, Tolazoline, Phenoxybenzamine.