Fildena 100 As referenced before the dynamic drug element of Fildena 100mg is Sildenafil citrate, the famous medication market as Viagra by Pfizer. Sildenafil was first found by Pfizer in 1989 for the treatment of heart-related chest torment. It was acknowledged for clinical use in the US and Europe in 1998. In 2017 its patent lapsed and conventional adaptations began to come out. It works by deactivating a chemical present in our body called PDE5 or phosphodiesterase - 5 which causes expanded blood stream in the penis and can cause long and supported erection in guys.