Avanafil is a pde5 inhibitor approved for erectile dysfunction by the fda on april 27, 2012 and by ema on june 21, 2013. avanafil is known by the trademark names stendra and spedra and was developed by vivus inc. avanafil acts by inhibiting a specific phosphodiesterase type 5 enzyme which is found in various body tissues, but primarily in the corpus cavernosum penis, as well as the retina. other similar drugs are sildenafil, tadalafil and vardenafil. the advantage of avanafil is that it has very fast onset of action compared with other pde5 inhibitors. it is absorbed quickly, reaching a maximum concentration in about 30-45 minutes. about two-thirds of the participants were able to engage in sexual activity within 15 minutes.