VIAGRA® May also be referred to as: Sildenafil, Sildenafil Citrate. Viagra® is approved for the treatment of men who have difficulty achieving and maintaining an erection (impotence). CIALIS® May also be referred to as: Tadalafil. Cialis® is used to treat erectile dysfunction (ED) in men. The active ingredient in Cialis® tablets is Tadalafil. LEVITRA® May also be referred to as: Vardenafil HCl. Levitra® is approved for the treatment of men who have difficulty achieving and maintaining an erection (impotence). PROPECIA® May also be referred to as: Finasteride. Propecia® is approved for the treatment of men who have male pattern baldness on the top of the head and anterior mid-scalp region.