What is the difference between sildenafil, vardenafil, and tadalafil?

Sildenafil, Vardenafil, and Tadanafil are all drugs that help with erections, with the difference being that their medication duration is different. Sildenafil has a shorter duration of about 4 hours. Vardenafil takes about 12 hours, while Tadanafil can last for 36 hours. It is recommended that patients take medication under the guidance of a doctor.