Super Zhewitra contains vardenafil, a potent PDE5 inhibitor. When a man is sexually aroused, nitric oxide is released in the erectile tissue of the penis, which activates the enzyme guanylate cyclase. This enzyme increases levels of cyclic guanosine monophosphate (cGMP), leading to relaxation of the smooth muscles in the arteries of the penis and allowing blood to flow in, resulting in an erection. PDE5 enzymes break down cGMP, but vardenafil inhibits PDE5, allowing cGMP to accumulate and promoting sustained blood flow to the penis, which helps in achieving and maintaining an erection.