Fildena Professional contains sildenafil, it generally starts helping with erections in about 30–60 minutes. The effect requires sexual stimulation; it won't automatically cause an erection. U Uroweb +1 A few practical points: Timing: Taking it about 1 hour before sex is typical. Food: A heavy/high-fat meal can delay absorption, sometimes by about an hour. E European Medicines Agency (EMA) Duration: Fildena Professional   erectile effect generally lasts around 4 hours, although this doesn't mean you will have an erection continuously. P PubMed Dose: For ED, the usual starting dose is 50 mg, with 100 mg as the maximum recommended dose once daily. D DailyMed Do not use sildenafil with nitrate medicines such as nitroglycerin or isosorbide because of the risk of a dangerous blood-pressure drop. If you tell me the strength of your Fildena Professional (e.g., 50 mg or 100 mg), I can explain the expected timing and safety considerations for that dose.