However, the dose is usually not more than 80 mg 3 times a day. Some illegal “street” drugs called “poppers” such as amyl nitrate, butyl nitrate, or nitrite. In younger men with variable or situational ED, sexual performance anxiety or low self-esteem can lead to stress and anxiety that restricts blood flow to the penis at exactly the wrong moment. If you take too much sildenafil or take it together with these medicines, the chance for side effects will be higher. The best way to improve your erectile function is to take a holistic approach.Sildenafil is available through Hims by prescription in , , mg pills starting at $4 per dose. Brand-name Viagra is also available through Hims in , , mg pills starting at $ The Savings Offer and Program expire on 12/31/ For further information, call , visit , or write: Viatris Inc., P.O. Box , Mission, KS See risks & benefits. Learn more about what VIAGRA® (sildenafil citrate), a prescription treatment for ED. Common Viagra side effects may include: flushing (warmth, redness, or tingly feeling); headache, dizziness; abnormal vision (blurred vision, changes in color vision) runny or stuffy nose, nosebleeds; sleep problems (insomnia); muscle pain, back pain; or. upset stomach. This is not a complete list of side effects and others may occur.