Viagra (sildenafil)
VIAGRA (sildenafil) – a phosphidiesterase-5 (PDE-5) inhibitor drug commonly used to treat erectile dysfunction in men. The physiologic mechanism of erection of the penis involves release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. NO then activates the enzyme guanylate cyclase, which results in increased levels of cyclic guanosine monophosphate (cGMP), producing […]