Viagra Info

What is Viagra?

Viagra (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. Viagra may also be used for other purposes not listed in this medication guide.

What Viagra is used for

Viagra is used to treat erectile dysfunction, more commonly known as impotence, in men. This is when a man cannot get, or keep, a hard erect penis suitable for sexual activity. Viagra belongs to a group of medicines called phosphodiesterase type 5 inhibitors. It works by relaxing the blood vessels in your penis when you are sexually excited. This allows blood to flow into your penis, allowing you to get an erection in the natural way. Viagra will work only if you are sexually excited. Viagra will not increase your sex drive. Viagra is not for use in women. This medicine is available only with a doctor's prescription.

So, how exactly does Viagra work?

Viagra works by causing the smooth muscles in your blood vessels to relax, increasing blood flow around and lowering the blood pressure. The active ingredient in Viagra, sildenafil, is also a PDE5 inhibitor; and it is this in particular that specifies an increase in blood flow to the penis. When a man is sexually stimulated his penile arteries go through a process to relax and enlarge. As they enlarge, the veins that remove blood from the penis are compressed thus restricting blood flow out of the penis, causing an erection. Although erectile dysfunction was originally thought to be purely psychological, the discovery of Viagra refuted this and it is now common fact that the nerves and blood vessels play a key role. If the nerves and blood vessels that facilitate the process of an erection do not work then erectile dysfunction occurs.

Before taking Viagra

Do not take Viagra if you are also using a nitrate drug for chest pain or heart problems. This includes nitroglycerin (Nitrostat, Nitrolingual, Nitro-Dur, Nitro-Bid, and others), isosorbide dinitrate (Dilatrate-SR, Isordil, Sorbitrate), and isosorbide mononitrate (Imdur, ISMO, Monoket). 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:

  • heart disease or heart rhythm problems, coronary artery disease;

  • a recent history (in the past 6 months) of a heart attack, stroke, or congestive heart failure;

  • high or low blood pressure;

  • liver or kidney diseas;

  • a blood cell disorder such as sickle cell anemia, multiple myeloma, or leukemia;

  • a bleeding disorder such as hemophilia;

  • a stomach ulcer;

  • retinitis pigmentosa (an inherited condition of the eye);

  • a physical deformity of the penis (such as Peyronie's disease); or

  • if you have been told you should not have sexual intercourse for health reasons.

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.

FDA pregnancy category B: This medication is not expected to be harmful to an unborn baby. Do not use Viagra without telling your doctor if you are pregnant or plan to become pregnant during treatment. It is not known if sildenafil passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.