The active component of Zudena Pills is udenafil, the most recent PDE5 (phosphodiesterase type 5) inhibitor used to treat erectile dysfunction (ED). Zudena Pills (Udenafil) is the recently approved ED drug. Urologists prescribe the medication udenafil to treat erectile dysfunction. Among other erectile dysfunction medications, it is a member of the PDE5 inhibitor pharmaceutical class, which also includes vardenafil, tadalafil, sildenafil, and avanafil.