Cenforce contains sildenafil, and sildenafil is commonly used on an as-needed basis, so occasional use can be appropriate for erectile dysfunction when it has been prescribed or deemed safe for you. The usual starting dose is 50 mg about 1 hour before ***** activity, with a range of 25–100 mg depending on effectiveness and tolerability. It should not be taken more than once in 24 hours. D DailyMed +1 A few important points: Don't combine Cenforce with Fildena or another sildenafil product—they contain the same active drug. Don't combine it with tadalafil, vardenafil, or other ED medicines unless a doctor specifically directs you. Never use sildenafil with nitrate medicines such as nitroglycerin or isosorbide; this can cause a dangerous drop in blood pressure. F FDA Access Data Be cautious if you take alpha-blockers or certain blood-pressure medicines, as blood pressure can fall further. D DailyMed Seek urgent medical care for an erection lasting more than 4 hours. D DailyMed If you tell me which Cenforce strength you have (25, 50, or 100 mg) and what other medicines you take, I can explain whether that particular dose/use pattern is generally appropriate.