The most common side effects are headaches, feeling sick, indigestion and dizziness. However, if you take sildenafil with a high-fat meal, it will take longer for the medication to start to work. You are encouraged to report adverse events related to Viatris products by calling U. Patients should always ask their doctors for medical advice about adverse events. Sexual function data were also recorded by patients in a daily diary. Your health information should remain between your provider and yourself.The discount plan organization is Hippo Network LLC, One World Trade Center, Suite New York, NY , , help@test1.ru, test1.ru . Key facts. Sildenafil (Viagra) is a medicine used to treat erectile dysfunction (ED, also called impotence). Sildenafil works by helping to relax the blood vessels in the penis, allowing more blood to flow in and cause an erection. You should take sildenafil about an hour before planned sexual activity, so it has time to work. VIAGRA can cause your blood pressure to drop suddenly to an unsafe level if taken with certain other medicines. Do not take VIAGRA if you take any other medicines called “nitrates.” Nitrates are used to treat chest pain (angina). A sudden drop in blood pressure can cause you to feel dizzy, faint, or have a heart attack or stroke.