The Half-Life of Sildenafil Explained 2. It works by promoting muscle relaxation and vasodilation widening of the blood vessels , allowing greater blood flow to the penis. If you do have any mild side-effect reaction to Viagra, you can also consult your prescriber to see if a lower dose might work better for you. More satisfying sex for you and your partner. Make sure that you are being mentally or physically stimulated in order to get everything going and the medication will be able to take it from there. Viagra allows the blood vessels in the penis to relax and expand, boosting the blood flow to the area and making it easier to maintain a lasting erection.When taking Viagra for erectile dysfunction, take one 50mg tablet about 1 hour before sex. The effects usually last for 4 hours, and will only start to work once you’re sexually . Drug Images What is Viagra? Viagra is a brand-name prescription drug that’s approved to treat erectile dysfunction (ED). With ED, you’re unable to have or maintain an erection. . phone Need help? Show this coupon to your pharmacist Print or send this coupon to yourself. Local pharmacy prices Choose a pharmacy to get a coupon location_on moses .