Slidenafil acts by blocking which enzyme?

Ans. (b) Phosphodiesterase 5 inhibitionRef. KD Tripathi 6th Ed. 1294-295* Sildenafil, Tadalafil and vardenafil are selective PDE-5 inhibitors effective in erectile dysfunction.* 5 a - REDUCTASE INHIBITOR# Finasteride is competitive inhibitor of the enzyme 5a-reductase which converts testosterone into more active dihydrotestosterone responsible for androgen action in many tissues including prostate gland and hair follicles.# Used in treatment of BPH* Flutamide: A nonsteroidal drug having specific antiandrogenic, but no other hormonal activity.# Used in prostate CAAlso KnowTadalafil is the longest acting phospodiesterase inhibitor.