SPI-1972

Selegiline/phosphodiesterase-5 inhibitor(Sagene Pharmaceuticals, Inc.)

Vardenafil(Levitra, Staxyn)

C₂₃H₃₂N₆O₄S · Rx

Avanafil(Spedra, Stendra)

C₂₃H₂₆ClN₇O₃ · Rx

Tadalafil(Adcirca, Alyq, Cialis, Entadfi, Tadliq, Talmanco (previously Tadalafil Generics), Tadalafil Mylan, Tadalafil Lilly, Adcirca (previously Tadalafil Lilly), Yuvanci)

C₂₂H₁₉N₃O₄

phosphodiesterase inhibitors (Syntex)

Phosphodiesterase III inhibitors (VIVUS)

Phosphodiesterase inhibitor(Boehringer Ingelheim)

phosphodiesterase inhibitor (respiratory disease)

Phosphodiesterase V inhibitors (Plexxikon, Inc.)