Tadalafil, a phosphodiesterase type 5 (PDE5) inhibitor, is the active ingredient in Vidalista 20 mg , a medication used to treat erectile dysfunction (ED) in men. Tadalafil produces an erection by boosting blood flow to the penis during sexual stimulation. Usually taken orally, Vidalista 20 mg should be given half an hour to an hour before planned sexual activity.