Viagra is a new drug developed by Pfizer for the treatment of male impotency. Its pharmacological name is sildenafil citrate. It was approved by the US Food & Drug Administration in March 1998 for the treatment of male impotency.

What does Viagra® do?
Viagra increases the body's ability to achieve and maintain an erection during sexual stimulation. Viagra does not produce spontaneous erections; sexual stimulus must be present for erection to occur.

How does Viagra® work?
Viagra is dispensed as a pill and ingested orally. After absorption into the bloodstream, it functions as an inhibitor to an enzyme called phosphodiesterase 5 (PDE5) which is found primarily in the penis. The enzyme, PDE5 breaks down cyclic GMP. Cyclic GMP is produced during sexual stimulation, leading to penis erection. The longer the cyclic GMP is allowed to persist, the greater the chance for increased blood flow to the penis, thereby generating an erection.

How long does Viagra® remain effective after ingestion?
The half-life is approximately 4 hours. If is recommended that sexual stimulation commence from 30 to 60 minutes after Viagra is taken.

What happens if there is no sexual stimulation after Viagra® is taken?
Sildenafil, or Viagra, is excreted as metabolites from the body in feces and urine.

What is Viagra®'s success rate?
Viagra's success rate is about 75%.

Are there any side effects?
Yes, a small percentage of the study group experienced headaches, nausea, facial flushing, diarrhoea, urinary tract infection and visual changes to colour sensitivity.

Who should NOT take Viagra?
The main contraindication to prescribing Viagra® are people who suffer from a rare disease, retinitis pigmentosa, or those who are on nitroglycerin or nitrous oxide.

Recently, it has been reported that 16 Viagra® patients have died. While there is no direct evidence that Viagra caused the deaths, readers should be aware that sexual activity increases cardiac risk. Male impotence is often a side effect of more serious cardiovascular problems.

Viagra® MUST NOT be taken by men who are on medications containing nitrates, such as nitroglycerine tablets, as this could lead to dangerous lowering of blood pressure. There is evidence to suggest that Viagra may interact with other medications in such a way as to increase health risk. Men who have medical conditions, such as sickle cell anaemia, leukaemia, or multiple myeloma, or those with abnormally-shaped penis should also not take Viagra because of a possibility of producing a sustained erection.

Can I get Viagra® over-the-counter?
No, Viagra® should only be taken by prescription from a qualified physician. You must tell your doctor exactly what other medications you are taking. FDA regulations do not permit Viagra® to be purchased without a physician's prescription.

How often should Viagra be taken?
For those patients who have been prescribed Viagra® by their doctors, Viagra® should only be taken once per day, about 1 hour before sexual activity.

What Viagra® dosage is best?
Many physicians are now recommending Viagra therapy begin with 25mg dosage, the minimum. Standard dose is 50mg. Dosages higher than 100mg per day are NOT recommended.

Can Viagra® be combined with other treatments for erectile dysfunction?

The use of such combinations is NOT recommended, since no studies have been done to assess its safety and effectiveness.

Are there concerns about taking Viagra® for long periods of time?
Yes. Some health practitioners are concerned since little is known about Viagra's® long term effects.

It has been estimated that up to 30 million American men suffer from sexual dysfunction (impotence). Until recently, sexual dysfunction has been effectively treated with injections, surgery, and other procedures, many of which are painful and embarrassing. In March 1998, the FDA announced that Viagra® a new drug from Pfizer, Inc., has been approved as treatment for male sexual dysfunction.