Viagra helps children with heart-lung condition achieve improved quality of life

Viagra, a drug originally developed to treat heart disease, and now more commonly used to treat impotence, may also help children with a serious heart-lung condition to walk further and breathe more easily.

Researchers in a small study involving the drug, known generically as sildenafil, say the study needs to be repeated in a larger group to be accepted as credible, but initial results suggest a daily pill could be an alternative to current, cumbersome treatments.

Ian Adatia, an associate professor of pediatrics at the University of California, San Francisco Children's Hospital, who led the study, says that sildenafil compared favorably to drugs currently being used and had far fewer side effects.

Adatia says left untreated, these children usually die within one year of diagnosis. Apparently even with the best therapy, which entails continual intravenous infusion of the drug prostacyclin that helps lower the pressure in the pulmonary arteries, few patients live five years past diagnosis.

Adatia conducted the study while working at Toronto's Hospital for Sick Children in Canada.

In childhood pulmonary arterial hypertension, the blood pressure in the arteries that supply the lungs is extremely high, and as a result the small blood vessels in the lungs steadily narrow and their walls thicken, so they carry less blood.

This causes pressure to build as the blood backs up and the heart works overtime to cope properly. This then becomes a chronic condition known as heart failure, which causes patients to feel tired, dizzy and short of breath.

Prostacyclin treatment involves patients always carrying an infusion pump, and their parents must mix the drug daily.

Side effects include jaw and muscle pain and facial flushing, Adatia said.

Sildenafil works by relaxing the smooth muscle of blood vessels, expanding them and increasing the blood flow. When it was being tested on young men for development as a heart drug, doctors noticed the side-effect that the drug is now used for, it caused erections.

In the study varying doses of Viagra were given to 14 children aged 5 to 18 with pulmonary arterial hypertension for one year by Adatia's team.

After a year the children could walk considerably further, blood resistance dropped and the patients reported they could breathe more easily.

Most importantly, says Adatia, the side effects were minimal, the drug was very easy to take, and there were no changes in liver or kidney function.

The study is published in the journal Circulation.