Vidalista 40 mg is a tadalafil-containing medicine marketed for the treatment of erectile dysfunction (ED). Tadalafil belongs to a group of medicines called PDE5 inhibitors. It works by relaxing blood vessels and increasing blood flow to the penis when sexual stimulation occurs, helping men achieve and maintain an erection. Tadalafil is known for its relatively long duration of action, with effects potentially lasting up to about 36 hours. This does not mean an erection lasts for 36 hours; sexual stimulation is still required, and the medicine does not increase sexual desire.