Virekta Tadavir (Tadalafil 20mg) is a Cialis generic tablet for the treatment of erectile dysfunction. Cialis is a well-known and very popular ED treatment because it remains active in your body for 36 hours and it has come to be known as “the week-end pill”. In clinical studies where men with erection problems were given Tadalafil 20mg, 8 out of 10 men reported getting erections strong enough for vaginal penetration. These clinical studies are important because they included men with a range of erectile dysfunction severities and a variety of causes. A few of the men did report experiencing mild side effects, but most of them did not experience any side effects. The recommended dosage is one tablet 30 to 60 minutes before sexual activity.