buy Zhewitra-20 is used for erectile dysfunction and impotency in male. Zhewitra 20  is a PDE5 inhibitor that inhibiting PDE5, it releases more of cGMP in the Corpus Cavernosum of a penis.Avoid smoking if take this medication.Take this medicine in the dose and duration as advised by your doctor. It should be taken with full glass of water before any sexual intercourse with or without food.