Fildena 100 is one of the most contentious drugs to hit the market in the last few decades. Fildena 100 quickly enters your system and starts working after about an hour, though you can take it anywhere between 30 minutes and 4 hours before sexual activity. The study, which was published in the Annals of Internal Medicine in August 2003, discovered that ED is common among older men and that sexual function deteriorates significantly after the age of 50. Erectile dysfunction is defined as the inability to generate or maintain an erection that is sufficient for both partners' sexual enjoyment. When taking ED medications like Viagra, it's best to avoid alcohol.