Sildisoft Tablet contains sildenafil (for example, Sildisoft 100 mg is marketed as sildenafil 100 mg), it is taken before sex because it helps men with erectile dysfunction (ED) get and maintain an erection. S SS Medex +1 Why before sex? Sildenafil increases blood flow to the penis when you are sexually aroused. It does not automatically cause an erection or increase sexual desire. D DailyMed It Sildisoft Tablet works best when taken about 1 hour before sex. It can be taken roughly 30 minutes to 4 hours beforehand. Don't take it more than once in 24 hours unless your doctor specifically instructs otherwise. M MedlinePlus +1 A heavy/high-fat meal can delay its effect. D DailyMed Important: Sildenafil can dangerously lower blood pressure when combined with nitrate medicines such as nitroglycerin or with “poppers.” D DailyMed If you take heart medicines or have heart disease, check with a doctor before using it. If you tell me the strength written on your Sildisoft strip (e.g., 50 mg or 100 mg) and whether you're taking any other medicines, I can explain the usual safe way to take it.