Supplies of drugs to doctors have been delayed by new rules triggered by illegal sales of the anti-impotence drug Viagra. The rules have ended the practice of making prescription-only drugs available to hospitals, clinics and pharmacists immediately after being registered by the Pharmacy and Poisons Board. Suppliers will now have to wait for the drugs to go before the Legislative Council for classification as 'prescription-only medicine' and then be gazetted. The change means the time needed for new drugs to reach the patients - previously about three months from their release - will be lengthened. The executive director of the Hong Kong Association of the Pharmaceutical Industry, Robert Siu Shu-yok, said his members were losing out. He said drug companies had only seven or eight years to market drugs before their 20-year patent ran out, because so long had been spent on research. 'A few months would make a big difference and a substantial loss in revenue,' said Mr Siu. The release of the first batch of new drugs affected by the amended procedures has been delayed since they received permission to register in July. The Pharmacy and Poisons Board decided to amend the procedures in June after it emerged that Viagra was being sold without prescription. As Viagra had been approved before the legislation declaring it a 'prescription-only' drug, it was hard to prosecute those selling it illegally. A Department of Health spokesman said: 'This is to close a possible loophole in which the registration of a drug takes place before the legislative amendments are approved. 'Drugs sold without prescription can be a hazard to public health.' Wong Ka-hing, acting consultant in charge of programmes concerning HIV at the Department of Health, said he obtained drugs from overseas, skipping registration, when individual patients needed urgent treatment. He said it would be more convenient if new drugs could be readily available for all patients. The chairman of the Public Doctors' Association, Poon Tak-lun, said the delay would lengthen the process of approving the use of drugs. 'The Hospital Authority has to consider the cost of the drugs and check if they cause any side-effects,' he said. 'I am still waiting for a new medicine to treat arthritis. It would be better if we could eliminate unnecessary delay.'