Erectile dysfunction phosphodiesterase type 5 inhibitors

UROLOGICAL DRUGS ERECTILE DYSFUNCTION Phosphodiesterase type 5 inhibitors... 

Erectile dysfunction is treated by local or systemic application of vasodilator drugs. The most effective is sildenafil, a phosphodiesterase-type 5 inhibitor. 

Phosphodiesterase type 5 inhibitors are commonly prescribed for erectile dysfunction and include sildenafil, vardenafil,... 

Sildenafil It is orally active selective inhibitor of phosphodiesterase type 5 useful in treatment of erectile dysfunction. It results in reduced breakdown of cyclic guanosine monophosphate (cGMP) which is responsible for nitric acid (NO) mediated vasodilatation in corpora cavernosa. Thus inducing an erectile response to sexual stimulation. It has no direct relaxant effect on smooth muscle of corpus cavernosa and has no effect in absence of sexual stimulation. 

Terrett, N. K. Bell, A. S. Brown, D. Ellis, P. 1996. Sildenafil (Viagra), a potent and selective inhibitor of type 5 cGMP phosphodiesterase with utility for the treatment of male erectile dysfunction. Bioorg. Med. Chem. Lett., 6,1819-1824. 

Snow KJ. Erectile dysfunction in patients with diabetes mellitus advances in treatment with phosphodiesterase Type 5 inhibitors. BrJ Diab Vase Dis 2002 2 282-287. 

Porst H, Rosen R, Padma-Nathan H, et al. Efficacy and tolerability of vardenafil, a new selective phosphodiesterase type 5 inhibitor, in patients with erectile dysfunction the first at home clinical trial. IntJ Impot Res 2001 13 192-199. 

Jackson G, Martin E, McGing E, etal. Successful withdrawal of oral long-acting nitrates to facilitate phosphodiesterase Type 5 Inhibitor use in stable coronary disease patients with erectile dysfunction. J Sex Med 2005 2 513-516. 

Another recent example is provided by the discovery of the use of sildenafil (Viagra Fig. 1.15), a phosphodiesterase type 5 (PDE5) inhibitor, as an efficacious, orally active agent for the treatment of erectile dysfunction [25,26]. Initially, this compound was brought to the clinic as an hypotensive and cardiotonic substance, but its usefulness in erectile dysfunction resulted unexpectedly from clinical observations made during a 10-day toleration study in Wales [27]. 

The erectile dysfunction group of drugs, of which sildenafil is most common, are potent inhibitors of cyclic guanosine monophosphate-specific phosphodiesterase type 5 (PDE-5). The other two available drugs are tadalafil (Cialis) and... 

The combination of organic nitrates and sildenafil citrate (Viagra) can precipitate life-threatening hypotension in patients with angina (112). Sildenafil is a selective inhibitor of cyclic GMP-specific phosphodiesterase type 5, which causes smooth muscle relaxation and vasodilatation, and is an effective treatment for male erectile dysfunction. More than 3.6 million prescriptions have been issued as of August 1998, and so far there have been 69 deaths, 12 of which were attributable to the interaction with nitrates, as reported to the FDA. 

Indications Erectile dysfunction, Hypertension Category Phosphodiesterase type 5 inhibitor Half-life 4 hours... 

Sildenafil is a selective inhibitor of phosphodiesterase type-5 that is orally effective in the treatment of erectile dysfunction. Its pharmacological actions are a consequence of prolonging the signaling actions of NO because this drug prevents cGMP hydrolysis by inhibition of a cGMP phosphodiesterase V subtype enriched in penile smooth muscle (1, 10, 143). 

Boolell M, Allen MJ, Ballard SA, Gepi-Attee S, Muirhead GJ, Naylor AM, et al. Sildenafil An orally active type 5 cycfic GMP-specific phosphodiesterase inhibitor for the treatment of penile erectile dysfunction. Int J Impot Res 1996 8 47-52. 

Sildenafil citrate is a phosphodiesterase type 5 inhibitor that enhances the effect of nitric oxide by inhibiting phosphodiesterase type 5 in the corpus cavernosum of the penis. This results in vasodilation, increased inflow of blood into the corpora cavernosa, and ensuing penile erection npon sexnal stimulation. It is indicated in the treatment of impotence related to erectile dysfunction of the penis. 

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