The effectiveness of Sildenafil has been reviewed in clinical studies. Click here for an email preview. These medicines prevent an enzyme called phosphodiesterase type-5 from working too quickly. Answer: No. Next review due on August 01, Is there any difference between Viagra and Sildenafil? When a man is sexually stimulated, his body’s normal response is to increase blood flow to his penis to produce an erection.Viagra Descriptions Sildenafil is used to treat men who have erectile dysfunction (also . Viagra. Compare prices and print coupons for Sildenafil (Generic Revatio and Viagra) . Typical dosing for Sildenafil (Viagra) The typical dose is to take 50 mg of sildenafil .