<prompt> First dose effect is shown byPrazocinFurosemideThyronormCeftazidime  <response>: Ans. is a i.e., Prazocin First dose effect postural hypotension is now uncommon and occurs mainly with drugs having an action on veins a-adrenoreceptor blockers like prazosin, ACE inhibitors when baroreceptors reflex is impared e.g. old age or with contracted intravascular volume following diuretics -- Lawrence 9thep. 489 