Viagra: Not Just for Erections

Exactly 15 years ago, Michael Allen took a call from a doctor in a small Welsh town that gave the first hint of a revolution to come. The doctor had been running a small clinical trial testing a new drug to treat angina. The future for the drug, known as UK-92480. was looking bleak: other trials had showed that it did not have much impact on the disease, and indeed was less effective than existing treatments.

When the doctor gave his progress report to Allen, clinical project manager at drug giant Pfizer, he mentioned some side effects among the healthy volunteers in the trial in Merthyr Tydfil. These included indigestion, back pain -- and, the doctor added, erections.

Five years and much research later, Pfizer applied for marketing approval for the drug -- not for angina, but for male impotence. Ten years on, and Viagra has been used by more than 30 million men worldwide for erectile dysfunction.

It is also finding a host of new uses, too. The drug that nearly didn't make it is being used or investigated for the treatment of more than a dozen diseases and health problems. Researchers say it could turn out to be as versatile as Aspirin.

Conditions being assessed for treatment with Viagra include jet lag, heart failure, premature ejaculation, diabetes symptoms, multiple sclerosis, pain, premature birth, chronic pelvic pain, memory loss, Reynaud's phenomenon, and strokes.

In Egypt, Viagra has been used to save unconsummated marriages; in Argentina, it has been investigated as a new therapy for jet lag; in Israel, researchers have found that it can help cut flowers survive for longer.

Jet lag

Viagra may speed up recovery from jet lag, according to research at the Universidad Nacional de Quilmes in Buenos Aires. The brain's master clock controls the sleep-wake cycle by releasing hormones and neurotransmitters that regulate a wide range of functions. It's thought that an enzyme called cGMP plays a role in the regulation of the clock; Viagra boosts its effects by stopping it from being broken down by another enzyme, PDE5. The researchers found that animals injected with the drug adapted faster to light changes, suggesting that Viagra speeds up the time it takes the body clock to adapt to jet lag.

Erectile dysfunction

Now approved by regulatory authorities in more than 20 countries, Viagra was the first effective oral therapy available to men with erectile dysfunction. Until its release, the mainstays of therapy were injections and vacuum erection devices. In men with the condition, the nerves or blood vessels that play a part in the erection process don't work properly. The drug works by increasing the blood flow to the penis. According to a report from Auburn University in Alabama, the drug can combat impotence resulting from a wide range of causes, including side effects from other drugs, psychological problems, ageing, and diseases like type-2 diabetes, Parkinson's disease, depression and kidney failure.

Stroke

More than 80 stroke patients are being given Viagra in a trial starting this month in Detroit. Doctors believe that if given within three days of a stroke, the drug could help both men and women regain and improve movement, speech and thinking via its effect on the molecule cGMP, which is thought to create new cells in the brain. The trial follows successful work with animals and a small number of patients. "What we found is that we can use Viagra to create new brain cells," said Dr Michael Chopp, scientific director of the Neuroscience Institute at the hospital. "When animals with stroke are treated with Viagra, the drug provides very significant neurological functional benefit. They do much better."

Underweight babies

Doctors have been using Viagra in a trial with pregnant women as a therapy for intrauterine growth restriction, in which the fetus is smaller than expected for the number of weeks of the pregnancy. The condition is estimated to affect around 5 per cent of births in the UK. It's thought that the drug increases blood supply to the womb and placenta so that more nutrients and oxygen get through to the fetus, which can then carry on growing in the womb and is not born as prematurely as it might otherwise have been. Viagra works in this case by acting on an enzyme called PDE-5, which allows blood vessels to expand and increases blood flow to the baby.