Zhewitra 40 mg is commonly marketed as containing vardenafil, a PDE-5 inhibitor used to treat erectile dysfunction (ED) in adult men. Vardenafil works by increasing blood flow to the penis when sexual stimulation occurs. It does not increase sexual desire and cannot produce an erection without sexual stimulation. A key safety point is that 40 mg is above the usual maximum recommended vardenafil dose of 20 mg for ED. Higher doses may increase the risk of side effects without necessarily providing better results. Therefore, Zhewitra 40 mg should not be taken without medical supervision.