London, Nov 19 (IANS): The sex-enhancing drug Viagra may help people at risk for diabetes by improving insulin sensitivity in them, a first-of-its-kind study has revealed.

The erectile dysfunction drug sildenafil, sold as Viagra and other brand names, inhibits an enzyme resulting in relaxation of smooth muscle and increased blood flow.

Sildenafil is used to treat erectile dysfunction and pulmonary arterial hypertension.

In animal studies, researchers from Vanderbilt University Medical Centre in the US have found that sildenafil also can improve insulin sensitivity, the uptake of glucose from the bloodstream by muscle.

This action can lower the level of circulating glucose, and potentially reduce the risk of diabetes.

While further studies are needed to determine whether long-term treatment can prevent the onset of diabetes in high-risk patients, "sildenafil and related drugs could offer a potential avenue for addressing the rising number of diabetes diagnoses", said Nancy J. Brown, chair of the department of medicine at Vanderbilt.

For the study, overweight individuals with prediabetes were randomly assigned to receive sildenafil or placebo (inactive drug) for three months.

Of the 42 participants, those treated with sildenafil were significantly more sensitive to insulin, the researchers reported in the Journal of Clinical Endocrinology and Metabolism.

Sildenafil and related drugs prevent the specific enzyme from breaking down a chemical in the body called “cyclic GMP” which relaxes blood vessels and increases insulin sensitivity.

"But unlike some other methods of raising cyclic GMP, sildenafil did not decrease an anti-clotting chemical in the body," the Vanderbilt researchers reported.