Drug with a first dose effect:

(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.