Often, these are prescribed for chest pain called angina. This medicine works best when you take it on an empty stomach an hour before sex. If you experience chest pain, dizziness, or nausea during sex, seek immediate medical help. A newer form of the medicine that dissolves on the tongue might work faster than the pill that you swallow. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide.If you have these symptoms, stop taking VIAGRA and contact a doctor right away. have or have had heart problems such as a heart attack, irregular heartbeat, angina, chest pain, narrowing of the aortic valve, or heart failure. have low blood pressure, or high blood pressure that is not controlled. Viagra Coupons, Prices, and Savings Card. Generic Names: Sildenafil Citrate. Brand Names: Revatio. Sildenafil is used to treat male sexual function problems (impotence or erectile dysfunction-ED). Learn more about Viagra oral. 1. This is a generic drug. Even if this drug is covered by Medicare or your insurance, we recommend you compare prices. Viagra Dosage and Use Tips for First-Timers. Viagra dosage for erectile dysfunction (ED) is usually milligrams (mg), but those over 65 may start at 25 mg. Your doctor will also need to.