How Viagra works

Viagra has become one of the most popular drugs in the USA. It is used to treat erectile dysfunction: the inability of some men to get or maintain an erect penis. The European Medicines Evaluation Agency will have to give its consent before the drug can go on sale in Britain, but Pfizer Inc - the company that manufactures the drug - hope to get this approval by the autumn.

How does Viagra work?
Viagra, also known as Sildenafil, does not directly give a man an erection. It works by boosting the natural mechanism that leads to an erection. When a man is sexually aroused, certain tissues in his penis relax. This allows large amounts of blood to flow into the muscle, thus producing an erection. Viagra helps by elevating the levels of the chemical that causes the tissues to relax. These effects were discovered accidentally. The drug was originally developed to improve blood supply to the heart in angina sufferers.

Who can it help?
The drug can help impotence associated with diabetes, spinal cord injuries, prostate surgery, and even impotence with mysterious causes. Viagra was tested on 3,000 men with varying degrees of impotence. It achieved a success rate of 60-80%, depending on the dosage.

Does it have side-effects?
In a small number of cases, people who have taken Viagra have complained of headaches, flushing and stomach-ache. It can also cause some visual problems, including an increased sensitivity to light, blurred vision or an inability to tell the difference between blue and green. Men who are already taking medicines that contain nitrates, such as nitro-glycerine, are strongly advised not to use Viagra because the combination can lower blood pressure too much. There are also concerns about its safety following the deaths of a small number of American men who have taken the drug. The Food and Drug Administration is investigating.

What other treatments are available for impotence? Many men use vacuum devices or compression rings to get and keep an erection. It is possible to have an injection in the base of the penis to increase the flow of blood. Surgery and implants are also an option in some cases. There are also several other prescriptions and over-the-counter pills that have been recommended for impotence problems in men, but none of these have ever been proven to be as effective as Viagra.

This page contains basic information. If you are concerned about your health, you should consult a doctor.

Source: BBC