Zhewitra 40 mg contains the active ingredient vardenafil, which is a phosphodiesterase type 5 (PDE5) inhibitor. It is primarily used to treat erectile dysfunction (ED) in men. The mechanism of action of Zhewitra 40 mg is similar to other medications that belong to the same class of drugs, such as sildenafil (Viagra) and tadalafil (Cialis). During sexual arousal, the release of nitric oxide (NO) in the penis triggers the production of cyclic guanosine monophosphate (cGMP). This chemical relaxes the smooth muscles of the blood vessels in the erectile tissue of the penis, allowing increased blood flow into the penile arteries. https://www.genericday.com/zhewitra-40-mg.html