fildena 100 helps solve all sexual related problems besides impotence like sex life. It simply works by increasing the blood flow to the penis. Therefore, whenever a person takes this drug, Then the erection becomes easier and it lasts for about 4 to 5 hours. It is mainly used to help in the treatment of pulmonary hypertension.fildena 100 helps solve all sexual related problems besides impotence like sex life. It simply works by increasing the blood flow to the penis. Therefore, whenever a person takes this drug, Then the erection becomes easier and it lasts for about 4 to 5 hours. It is mainly used to help in the treatment of pulmonary hypertension.