Zhewitra 40 mg is a medication used to treat erectile dysfunction (ED) in men. It contains Vardenafil, which is a PDE5 inhibitor that works by improving blood flow to the penis, helping men achieve and sustain an erection when sexually aroused. Vardenafil works by inhibiting the PDE5 enzyme in the penis, which normally breaks down cGMP. By blocking this enzyme, it helps to increase cGMP levels, which relaxes the smooth muscle in the penis, allowing blood vessels to expand and increase blood flow, thus facilitating an erection.