Up to 4 hours after taking Fildena 200, the effects may still be felt. However, compared to 2 hours after taking Fildena 200, these effects are less potent at 4 hours. The effects of Fildena 200 occur at their greatest 60 minutes after taking the medication, thus this is when they are most noticeable. The medication Fildena 200 is used to treat erectile dysfunction. Up to four hours may pass before its effects start to enhance blood flow to the penis.