Vidalista 40 Tadalafil acts as the active ingredient in the drug. Vidalista 40 is mainly taken 1 hour before intercourse. The effect lasts for 36 hours after taking it. Vidalista 40 is the best drug to be used to solve the problem of impotence. Use Vidalista 40 only once a day. Vidalista 40mg should be kept away from small children and pets.