It's a cause for concern and not a cause for celebration

Health Minister Chua Jui Meng

The company, Pfizer Malaysia, said 40,000 Malaysians had been taking the anti-impotency pill regularly since it was made available on prescription more than two years ago.

The study showed that half of the men were diabetic, while the rest suffered from hypertension, high cholesterol levels or were smokers.

Health Minister Chua Jui Meng said the revelation was "alarming".

"It's a cause for concern and not a cause for celebration," he told the Star newspaper.

Big seller

He said some men might be tempted to use the drug to enhance sexual performance, rather than because of medial problems.

Viagra earned Pfizer over $1bn last year

Viagra was launched in the US in 1998 and earned Pfizer more than $1bn in sales last year.

The drug is available on prescription in major pharmacies in Malaysia for $10 (38 ringgit) for a 50mg pill and $12.60 for a 100mg pill. Malaysia has a total population of about 22- million people.

In 1999, two months after the drug was first marketed in Malaysia, the organisers of a charity golf tournament decided to withdraw a year's supply of Viagra as the top prize.

Pfizer Malaysia was one of the sponsors of the tournmanent, but there were a number of complaints that the prize would encourage abuse of the drug.