Zhewitra 20 mg is a medication used to treat erectile dysfunction (ED) in men. It contains vardenafil, which is a phosphodiesterase type 5 (PDE5) inhibitor. Zhewitra 20 mg is a medication used to treat erectile dysfunction (ED) in men. It contains vardenafil, which is a phosphodiesterase type 5 (PDE5) inhibitor. Vardenafil, the active ingredient in Zhewitra, works by inhibiting the enzyme phosphodiesterase type 5 (PDE5), which regulates blood flow. By inhibiting PDE5, vardenafil increases blood flow to the during stimulation, resulting in an erection. The recommended dosage of Zhewitra is 20 mg, taken orally with water, approximately 25 to 60 minutes before anticipated activity. The onset of action may vary among individuals, but it is generally effective within 30 minutes to 1 hour after ingestion. Zhewitra should not be taken more than once a day.