The duration of the effect for Fildena 50 generally lasts between 4 to 6 hours. However, this time frame can vary depending on several individual factors. When taken correctly, Fildena 50 can help maintain an erection for a sufficient amount of time to engage in sexual activity. It is important to note that Fildena 50 does not cause an erection automatically; sexual stimulation is still required for the drug to work.