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What is First dose effect is shown by and explain in detail?
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 9th/ep. 489