A new anti-impotence drug should be tested on Asian men before it is introduced in Hong Kong, urologists have warned. The drug, Uprima, is expected to be approved in the US and the European Union. The manufacturers, Abbott Laboratories (US) and Takeda Chemical Industries, anticipate it will be available in Hong Kong by the end of next year - but there is no requirement that it be tested locally. 'We intend to file an application with the Government by the middle of this year and, depending on the approval, we anticipate Uprima will be on the market by the end of 2002,' said Abbott Laboratories' marketing director Pingo Luk. However, SAR urologists are concerned about the side effects of the drug, such as vomiting and nausea, and say it first needs to be tested on Asian men. 'The potential side effects of Uprima are a worrying thing. The drug can produce nausea, sweating, vomiting - and yawning,' said Dr Andrew Yip Wai-chun, a consultant urologist at Kwong Wah Hospital. 'There haven't been any trials on Asian men, which is a worry because of the differences between Western and Asian men, such as the metabolism. If they really want to introduce it in Hong Kong, a pilot trial would be necessary.' Dr Yip estimates that about 10 per cent of Hong Kong's men, or 200,000, suffer from erectile dysfunction. According to the Department of Health, trials of Viagra were undertaken voluntarily on the mainland by manufacturer Pfizer. There is no legal requirement for drugs manufactured overseas to be tested in Hong Kong before approval. 'So long as the drug works and is proven, race would not come into it,' a department spokesman said. 'There is no single rule, but in general, if a drug is manufactured in the US, for example, we would want test results from that country.' Uprima acts on the central nervous system, whereas Viagra works on the tissues of the sex organ. The new drug improves the signals transmitted to the section of the brain that receives sexual stimulus. Overseas tests have shown a 60 to 70 per cent response rate, according to Dr Yip. The success rate of Viagra is about 80 per cent. Unlike Viagra, which takes up to 60 minutes to take effect and lasts for about four hours, the new drug dissolves under the tongue. It works in as little as 20 minutes and lasts about five hours. Dr Peter Chan Siu-foon, chief of the Urology and Kidney Transplantation division at the Chinese University, said it might be difficult to find patients willing to take part in a trial because of the drug's side effects. 'Uprima can cause nausea and vomiting and it can lower blood pressure to the extent where a patient can faint,' he said. 'This could be very dangerous if a person is driving a car, for example.' But Uprima's manufacturers said the side effects were not a serious problem. 'All products can have side effects, such as headaches and so on. It is pretty common in drugs,' said Mr Luk. Despite Viagra's position as the market leader, he was confident the company's product could compete. 'The product has not yet been officially approved, so we haven't come to a decision on a pricing strategy yet - but I would say it will be priced competitively,' he said. Pfizer, which introduced Viagra to Hong Kong in 1999, said there was always a risk with carrying out clinical trials. 'We chose to do tests in China because we have confidence in the drugs and because we understand there are differences between Asian and Western markets,' medical affairs manager Steve Sze said.