Hospital pharmacists mixed up liver and gout tablets, accidentally giving at least one patient the wrong pills, it was revealed yesterday. The mistake was discovered on Wednesday, when Tuen Mun Hospital dispensary staff found packets of frusemide - a diuretic mainly used for those with liver disease - in a tray intended for gout medicine. The side-effects of frusemide include nausea and vomiting. Allopurinol, which should have been dispensed, reduces uric acid levels in people who suffer chronic gout. Acting hospital chief executive Dr Lau Kwok-wai said frusemide was initially thought to have been dispensed to 16 patients. 'It happened during the refilling procedure at the start of the clinic. 'Somebody put it in the wrong tray and it was discovered at the end of the session,' Dr Lau said. Telephone calls and house visits managed to track down 15 patients, but only one had received the wrong drug. 'Fortunately, we contacted him before he took the drug and asked him to come back,' he said. Taking frusemide would have made the patient urinate more frequently and, if taken long-term, could have affected his heartbeat, Dr Lau said. Hospital staff were still trying to find the 16th patient last night, while an investigation would determine whether guidelines needed to be tightened. The blunder is one of a series of mistakes at the pharmacies of public hospitals and clinics during the past year. In February, concentrated chloroform was accidentally added to cough medicine given to 36 patients at the Central Kowloon Health Clinic. In November, pharmacists at the Cheung Sha Wan Jockey Club Clinic handed out mouthwash instead of anti-fever syrup for 144 toddlers. The errors, at Department of Health clinics, revealed staff shortages and a lack of guidelines, an Ombudsman's inquiry concluded last month. Errors have also dogged the Hospital Authority, which runs the Tuen Mun Hospital. They include last Friday's accidental injection of a 17-month-old baby with the heart-slowing drug potassium chloride, in Princess Margaret Hospital.