Blue wonder: Happy birthday Viagra

Viagra doesn't just save sex lives, it can also treat jet lag, MS and strokes. Roger Dobson on the fifteenth birthday of a modern-day wonder drug

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.

In Israel, a trial is underway where pregnant women will be given 25mg of Viagra. If doing so allows the babies to spend just a few more days in the womb, this could make a big difference to the child's long-term health.

Multiple sclerosis

Estimated to affect more than 85,000 people in the UK – twice as many women as men – MS is the most common disabling disease of the central nervous system in young adults. MS is thought to be caused when the immune system attacks the sheaths that protect our nerves. The damage caused disrupts the way that messages are carried to and from the brain, interfering with a wide range of body functions.

An Auburn University report suggested that Viagra may protect against some degeneration: "It has been shown to protect multiple sclerosis patients from neurodegeneration through increased grey matter perfusion in the brain," the researchers said.

Memory and learning

A number of studies have suggested that taking Viagra can boost memory and learning skills. Just how it does so, however, it not clear. One theory is that it triggers increased blood flow and improved glucose processing in the brain; another is that levels of cGMP, which Viagra increases, have to be kept high for peak learning ability.

Production of cGMP decreases with age and may contribute to age-related memory decline, according to Auburn University researchers: "Viagra offers a new strategy for memory improvement and a novel therapy for Alzheimer's disease in the future," they say.

Unconsummated marriages

Doctors at Cairo University Hospital have successful used Viagra to tackle the tricky problem of unconsummated marriages. Of the 35 patients in one study, 32 were able to overcome their marital problems after taking Viagra. In all, 23 patients needed the drug for less than a month, five for up to three months and four for longer than that. "The aim was to evaluate the effectiveness of short-term use in the management of unconsummated marriages diagnosed to be mainly psychogenic in origin," said the researchers. "Viagra is effective as a short-term treatment option in the management of unconsummated marriages."

Raynaud's phenomenon

A common, painful condition, caused by an interruption of blood flow to the fingers or other extremities, in severe cases Raynaud's phenomenon can lead to gangrene. A number of trials have shown that Viagra can be highly effective in treating it, both for men and women. One trial showed a halving of symptoms; in another, the symptoms of some patients disappeared altogether. "I have successfully treated 10 patients with Raynaud's phenomenon, using Viagra," said Dr Jack Lichtenstein, who carried out his study in Maryland. "In all patients, the results ranged from an excellent response to complete relief of symptoms." It is thought that Viagra works here by increasing blood flow and returning circulation to the affected areas.

Heart failure

Research in Italy suggested that Viagra improves the ability of patients with heart failure to exercise. The drug increased oxygen uptake, reduced pressure in the arteries, and improved the working of the lungs, said the Milan University researchers. Again, it's thought that the drugs does so by increasing levels of nitric oxide.

Wilting flowers

When researchers at Bar-Ilan University in Israel put cut flowers in a weak solution of Viagra – one-fiftieth the amount taken by men for impotence – the flowers survived for two weeks instead of one. They suspect the Viagra works through its effects on nitric oxide, which is also how the drug treats erectile dysfunction.

Pain

"Viagra has been shown to have immense potential for the treatment of pain in animals and humans," said pharmacologists at Auburn University.

Diabetes

Research on 40 men at the Instituto Mexicano del Seguro Social in Mexico showed that Viagra lowered levels of compounds associated with heart disease in patients with type-2 diabetes. The drug also improved glucose control.