Esculap is also known as Cialis. It is an oral drug used for treating impotence (the inability to attain or maintain a penile erection). It is part of a class of drugs called phosphodiesterase inhibitors that also includes sildenafil (Viagra) and vardenafil (Levitra).
Erection of the penis is caused by the filling of the penis with blood. Filling occurs because the blood vessels that bring blood to the penis increase in size and deliver more blood to the penis, and, at the same time, the blood vessels that take blood away from the penis decrease in size and remove less blood from the penis.
Sexual stimulation that leads to an erection causes the production and release of nitric oxide in the penis. The nitric oxide causes an enzyme, guanylate cyclase, to produce cyclic guanosine monophosphate (cGMP). It is the cGMP that is primarily responsible for increasing and decreasing the size of the blood vessels carrying blood to and from the penis, respectively, and causing the erection. When the cGMP is destroyed by another enzyme, phosphodiesterase-5, the blood vessels return to their normal size, blood leaves the penis, and the erection ends. Tadalafil prevents phosphodiesterase-5 from destroying cGMP so that cGMP stays around longer. The persistence of cGMP leads to a more prolonged engorgement of the penis with blood.
For most individuals, the recommended starting dose of Esculap is 20 mg per day taken before sexual activity. Depending on the adequacy of the response or side effects, the dose may be increased to 20 mg or decreased to 5 mg a day. The effect of Esculap 20mg may last up to 36 hours. Individuals who are taking medications that increase the blood levels should not exceed a total dose of 10 mg in 72 hours.