Usage: Used for the treatment of erectile dysfunction. A phosphodiesterase 5 inhibitor. Avanafil is a PDE5 inhibitor approved for erectile dysfunction by the FDA and EMA,it acts by inhibiting a specific phosphodiesterase type 5 enzyme which is found in various body tissues, but primarily in the corpus cavernosum penis and retina.Avanafil works the same way as the three other ED …