China Greatvista Chemicals

Tadalafil (Cialis)

Tadalafil is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. Tadalafil is in a class of medications called phosphodiesterase (PDE) inhibitors. It works by increasing blood flow to the penis during sexual stimulation. This increased blood flow can cause an erection. Tadalafil does not cure erectile dysfunction or increase sexual desire. Tadalafil does not prevent pregnancy or the spread of sexually transmitted diseases such as human immunodeficiency virus (HIV). It is a phosphodiesterase inhibitor that is similar to sildenafil (Viagra) and vardenafil (Levitra).

Penile erection is caused by the engorgement of the penis with blood. This engorgement occurs when the blood vessels delivering blood to the penis increase in size and increase the delivery of blood to the penis. At the same time, the blood vessels carrying blood away from the penis decrease in size and decrease the removal of blood from the penis. Sexual stimulation that leads to the engorgement and erection causes the production and release of nitric oxide in the penis. Nitric oxide then activates the enzyme, guanylate cyclase to produce cyclic guanosine monophosphate (cGMP). The cGMP is primarily responsible for increasing and decreasing the size of the blood vessels carrying blood to and from the penis, respectively. Tadalafil prevents an enzyme called phosphodiesterase-5 from destroying cGMP so that cGMP persists longer. The longer cGMP persists, the more prolonged the engorgement of the penis.

When sexual stimulation causes the local release of nitric oxide, inhibition of PDE5 by tadalafil produces increased levels of cGMP in the corpus cavernosum. This results in smooth muscle relaxation and inflow of blood into the penile tissues, thereby producing an erection. Cialis (tadalafil) has no effect in the absence of sexual stimulation.

Cialis (Tadalafil) is a second generation selective phosphodiesterase 5 (PDE-5) inhibitor medication - Viagra (Sildenafil) being the first generation. PDE-5 inhibitors like Tadalafil work by blocking an enzyme called phosphodiesterase-5, or PDE-5. This helps the smooth muscles in the penis relax and widen, which allows for more blood to enter, thus increasing the body's ability to achieve and maintain an erection during sexual stimulation. Tadalafil will not work to cause an erection without physical stimulation to the penis, such as that occurring during sexual intercourse.