P.E.A.N.U.T.S + Phosphodiesterase Inhibitors Type V

Today's lecture was about treatment of heart failure. I missed 2 hours lecture on heart failure last Friday because I have other program in UKM, Bangi. Please refer to Pertemuan bersama Badan Penaja Anda!!. So, I learned only positive inotropic agents. They are digoxin, beta-agonists and the phosphodiesterase inhibitors. But, this entry will cover only on Phosphodiesterase Inhibitors Type V. (^_^)'

Left picture shows how the stimulation of Nitric Oxide (NO) release from nitregic nerves to produce cGMP breakdown causes vasodilation. Thus, relaxation. And men below are related to the mechanism. How?? On the cellular level, activation of guanylate cyclase enzyme by NO leads to the conversion of guanosine triphosphate to cyclic guanosine monophosphate (cGMP). This process further leads to elevated intracellular second messenger concentrations and causes an efflux of intracellular calcium, thus leading to smooth-muscle relaxation. Nitric oxide is released from parasympathetic nerves and endothelial cells and also by the inhibition of alpha-adrenergic neurons in the arterial and trabecular smooth muscle during sexual stimulation. After arousal and ejaculation, the cGMP has to be got rid of and an so an enzyme known as phosphodiesterase-5 (PDE5) forms which reacts with the cGMP and removes it.

When men get older, the most common disease occur is erectile dysfunction. The condition where men have not enough or insufficient erection (hardening of the penis) for penetration. The intake of Phosphodiesterase Inhibitors Type V inhibit breakdown of cGMP in corpus cavernosum tissue. Read more about it, here. It can increase level of cGMP and causes more prolong vasodilation in penis. Therefore, penis to be hard enough (erection). That will correct erectile dysfunction.

Google Image

Because of this effect, many pharmaceutical companies take advantage of this to gain profit by producing such drugs. There is very large market for these drugs. Companies want spend a lot of money on these sort of things to produce PDE5 inhibitors. That's why many older men take Viagra to improve their husband and wife lifestyle.

If the men already have angina problem, and take Nitrates (Isosorbide Dinitrate), then blood pressure really low. At the same time, the men also take Viagra. The 2 drugs will lower blood pressure with the same mechanism of action, blood pressure lowering more than required, therefore reflex tachycardia. So, heart rate which already quite fast, reflex tachycardia will make it worse. Old men with block coronary artery will just die half way.

Studying Heart Failure,
at 21-1.
(^_^) Happy.