Clubbers are mixing Viagra with a cocktail of drugs, including poppers, despite health warnings.

The first research into the use of Viagra in nightclubs has found that the anti-impotence drug is being used by clubbers in combination with drugs like Ecstasy, poppers and cocaine.

Fifteen people - 3% of those questioned - at a club in the North West admitted to taking the drug. Ten were men and five were women.

The research was done a month after Viagra was licensed for use in the UK.

It was available on a private basis, but the clubbers all obtained it illegally, mostly through dealers and friends.

One obtained it through the Internet.

Because they did not get the drug legally, none were aware that the manufacturers, Pfizer, warn against mixing it with nitrate-based drugs, such as poppers.

Positive effects

However, all experienced positive experiences with Viagra and said they would use it again.

Effects included increased sexual desire, enjoying sex more, having longer-lasting, better orgasms and feeling generally "loved-up".

Dr Fiona Measham from Manchester University, who was involved in the research, said the effect could have been due to the cumulative effect of Viagra and the other drugs the clubbers had taken.

Clubbers are not aware of the health risks of mixing Viagra

It could also be psychological because of the hype surrounding the anti-impotence drug.

However, Dr Measham said the medical view was that Viagra did not work on people with no sex problems and none of the clubbers said they had sex problems.

Some researchers have warned that Viagra could destroy penile tissue in healthy men, actually causing impotence.

Negative effects

The only negative side effects reported were headaches, feeling intoxicated and genital soreness.

Dr Measham said the genital soreness could be related to the people having more sex.

The feeling of intoxication and lack of inhibitions on the dance floor could be due to the mixture of different drugs the clubbers were taking.

This included mainly cocaine, cannabis, ecstasy, alcohol and GHB, which has been compared to date rape drug Rohypnol.

Dr Measham said it was known that Viagra and nitrate-based drugs could lower blood pressure to dangerous levels.

But it was not known what the affect of illegal drugs were on Viagra.

"Viagra dilates the blood vessels and stimulants like amphetamines, cocaine and ecstasy put pressure on the circulatory system so there could be long-term physical consequences of using them in combination," said Dr Measham.

"Many are very knowledgeable about some drugs, for instance, they know to take a lot of water with ecstasy, but they don't know what the effect of mixing drugs is. We are all in the dark on this to some extent," she added.

The Viagra research is part of a big two-year study, funded by the Economic and Social Research Council, on the health of clubbers. It will be published next year.

Dr Measham said one of the early findings, reflected in the Viagra research, was how willing young people were to experiment with new drugs.