(sildenafil) relaxes muscles and increases blood flow to particular areas of the body.
Viagra is used to treat erectile dysfunction (impotence) in men. Another brand of sildenafil is Revatio, which is used to treat pulmonary arterial hypertension and improve exercise capacity in men and women.
Do not take Viagra while also taking Revatio, unless your doctor tells you to.
You should not use Viagra if you are allergic to sildenafil.
Do not take Viagra if you are also using a nitrate drug for chest pain or heart problems. This includes nitroglycerin, isosorbide dinitrate, and isosorbide mononitrate. Nitrates are also found in some recreational drugs such as amyl nitrate or nitrite ("poppers"). Taking Viagra with a nitrate medicine can cause a sudden and serious decrease in blood pressure.
Contact your doctor or seek emergency medical attention if your erection is painful or lasts longer than 4 hours. A prolonged erection (priapism) can damage the penis.
Stop using this medicine and get emergency medical help if you have sudden vision loss.
You should not use Viagra if you are allergic to sildenafil.
Do not take Viagra if you are also using a nitrate drug for chest pain or heart problems. This includes nitroglycerin, isosorbide dinitrate, and isosorbide mononitrate. Nitrates are also found in some recreational drugs such as amyl nitrate or nitrite ("poppers"). Taking Viagra with a nitrate medicine can cause a sudden and serious decrease in blood pressure.
To make sure Viagra is safe for you, tell your doctor about your other medical conditions, especially:
Viagra can decrease blood flow to the optic nerve of the eye, causing sudden vision loss. This has occurred in a small number of people taking Viagra, most of whom also had heart disease, diabetes, high blood pressure, high cholesterol, or certain pre-existing eye problems, and in those who smoke or are over 50 years old. It is not clear whether Viagra is the actual cause of vision loss. Stop using Viagra and get emergency medical help if you have sudden vision loss.
It is not known whether sildenafil passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.
Do not give this medication to anyone under 18 years old without medical advice.