Substance: Tadalafil
Country: Egypt
Form: 20mg/tablet
Amount: 30 tablets
Recommended Dosage: 20mg 2-4 hours prior to sexual activity
Description:
Tadalafil prevents degradation of cGMP by 5-phosphodiesterase (PDE5) in the corpus cavernosum. Nitric Oxide in the corpus cavernosum of the penis binds to guanylate cyclase receptors which results in increased levels of cGMP, leading to smooth muscle relaxation (vasodilation) of blood vessels. This has the effect of increased inflow of blood into the spongy tissue of the penis, causing an erection.
Tadalafil is a potent and selective inhibitor of PDE5, which is responsible for degradation of cGMP in the corpus cavernosum. The molecular structure of Tadalfil is similar to that of cGMP and acts as a competitive binding agent of PDE5 in the corpus cavernosum, resulting in more cGMP and better erections. Without sexual stimulation, and therefore lack of activation of the NO/cGMP system, Sildenafil should not cause an erection. Tadalafil is broken down in the liver by hepatic metabolism using cytochrome p450 enzymes, mainly CYP450 3A4(major route), but also by CYP2C9 (minor route) hepatic isoenzymes. Tadalafil is excreted as metabolites predominantly in the feces (about 80% of administered oral dose) and to a lesser extent in the urine (around 13% of the administered oral dose). If taken with a high-fat meal, absorption is reduced; the time taken to reach the maximum plasma concentration increases by around one hour, and the maximum concentration itself is decreased by nearly one-third. The advantage of Cialis over Viagra is its long half-life of 17.5 hours compared to 4 hours.
