Take sildenafil at around the same times every day. You might decide against buying Viagra Connect from the pharmacy, perhaps because you feel you need a different dose of Viagra, maybe you want a more cost-effective ED treatment or maybe the discretion of an online solution is more appealing to you. What should I do if I forget a dose? This can happen if you are sick with fever, diarrhea, or vomiting; sweat a lot; or do not drink enough liquids. ED can sometimes signal an underlying medical problem, like heart disease or diabetes , that needs to be treated separately. Pearlman says.Last updated on Uses Warnings Before taking Dosage Side effects Interactions FAQ What is sildenafil? Sildenafil relaxes muscles of the blood vessels and increases blood flow to particular areas of the body. Sildenafil under the name Viagra is used to treat erectile dysfunction (impotence) in men. Sildenafil (Liqrev, Revatio) is used to improve the ability to exercise in adults (Liqrev, Revatio) and children 1 year of age and older (Revatio) with pulmonary arterial hypertension (PAH; high blood pressure in the vessels carrying blood to the lungs, causing shortness of breath, dizziness, and tiredness). Generic Viagra (sildenafil) is an alternative to the branded Viagra drug that can be used for treating erectile dysfunction (ED). It’s now sold by many manufacturers, including online.