Generic versions of Viagra are medications that share the same active ingredients, concentration, and form as the brand-name Viagra. They have been proven to be bioequivalent through thorough absorption studies. These generics are designed to treat erectile dysfunction, a condition characterized by difficulties in achieving or maintaining an erection. The key component in both Viagra and its generic counterparts is Sildenafil Citrate, which functions as a phosphodiesterase type 5 inhibitor. The patent for Sildenafil Citrate expired in many Western European countries in 2013, paving the way for the production of generic forms. Some well-known generics include Kamagra, Slifeldrem, Sildenafil Actavis, Sandos, and Mylam.