Sildenafil can be taken up to four hours before sex, although it should be taken at least 30 minutes before. Men with erectile dysfunction (ED) can use Cenforce 130 MG to cure their condition. It contains sildenafil citrate, the same active component that is in the popular drug brand Viagra. When a man is sexually aroused, sildenafil citrate can aid improve erections by improving blood flow to the penis.