ED can sometimes signal an underlying medical problem, like heart disease or diabetes , that needs to be treated separately. Medicines that you take by mouth are called oral medicines. Its effects might last longer if you have mild to moderate ED. There were some reports of headaches and nausea, however. Deaths were first reported after approximately one year of use, and hence sildenafil, particularly chronic use, is not recommended in pediatric patients with PAH.AdWe stock a wide variety of off grid & grid tie solar equipment from controllers to panels. Shop Northern Arizona Wind & Sun for Low Prices, Expert Knowledge & Great Customer ServiceKnowledgeable Staff · 35 Years Running · Quick & Easy Checkout. Viagra is absorbed quickly into your body. It can start working within 30 minutes, but it may take a couple hours for some people. However, one study on Viagra found that about 70% of men achieved erections in 30 minutes, and more than 80% of men achieved erections within 45 minutes. For most men, the effects of Viagra will start within . Generic Viagra (sildenafil) is available as a , , , and milligram (mg) pill and in liquid form. It’s meant to be taken as needed — about an hour before sex — but shouldn’t be.