Viagra Corner: Dispatches from the Frontiers of Medicine

A RIVAL to Viagra may be launched in Britain in the next few months. The manufacturer of Vasomax claims its drug begins to work after half an hour, compared with Viagra's one hour start-up time.

US pharmaceutical giant Schering Plough is hopeful that the Government's Medicines Control Agency will award a licence to market Vasomax by April.

The drug has already been on sale in Mexico for three months, having undergone successful clinical trials there. The manufacturer is also seeking permission to market the drug in America.

Both drugs help impotent men to achieve and sustain erections, but they work in different ways. Viagra acts on an enzyme that regulates blood flow to the penis. Vasomax , an alpha blocker, stops nerve impulses that control the tiny muscles surrounding blood vessels in the erectile tissue. Schering Plough says that its product has another advantage over Viagra - it can be used my men who take nitrate drugs for angina and heart conditions.

The launch of the new drug seems unlikely to bring down the high cost of restoring potency - at least for the time being. Vasomax is expected to cost pounds 4-pounds 5 for each 40 milligram tablet, while Viagra sells for pounds 4.84 per tablet.