The last and the best tip is that you should look for a company that has a good customer service. Take sildenafil up to 4 hours before you want to have sex. Without the stimulation to produce nitric oxide, there is no cGMP build-up and no erection. The medicine will come with a plastic syringe or spoon to help you take the right amount. The more reviews the better, because the more customers will tell you the truth about the Viagra online. Children 1 year of age and older weighing 45 kilograms kg or more—20 mg 3 times a day. Follow your doctor’s orders or the directions on the label.Drug Images What is Viagra? If you have erectile dysfunction (ED), your doctor may recommend that you take Viagra. It’s a prescription drug that’s used in . Viagra works by increasing blood flow to the penis which helps men get and sustain an erection long enough for sex. We offer Viagra at super extra low price. Typical dosing for Sildenafil (Viagra) The typical dose is to take 50 mg of sildenafil (Viagra) by mouth, about 1 hour before sex, as needed. The maximum recommended dose is mg. Don’t take sildenafil (Viagra) more than once daily (at any dose). Written by Brian Leonard, PharmD, BCACP, BCGP.