Sildenafil Citrate or Viagra is a drug that is most commonly used and know for the treatment of erectile dysfunction. and other male sexual function problems. The active ingredient in the drug is sildenafil citrate. sildenafil generic is generally used to increase blood flow to the penis to help a man get and sustain his erection to enhance sexual activity. If you have fluctuating blood pressure then you are advised to use this drug. sildenafil directly interferes with the blood flow. sildenafil dosage, sildenafil side effects, what is sildenafil