Two children overdosed on a heart drug after blunders by public hospital staff over a six-month period left another three patients injured, a Hospital Authority report says. Each child was accidentally dispensed 10 times the prescribed amount of digoxin from the same hospital. When the medicine was administered at home, they developed signs of toxicity and started vomiting. They were taken to hospital, where an antidote was applied. They suffered no permanent injury, the authority found. The second incident could have been prevented if the hospital had identified the underlying cause and rectified the problem after the first overdose, the authority's chief pharmacist, Lee Pak-wai, said. The overdoses occurred because pharmacy staff did not thoroughly check the dispensed drug against the prescription, according to an analysis of medication incidents reported in Hong Kong hospitals during the first half of last year. More than 170 patients were affected by drug blunders in public hospitals in the first six months of 1996, with the actual number of registered errors totalling 4,074. Although only four patients were injured through blunders requiring antidotes, another eight had to be monitored more intensively after errors in prescribing or administering medicines. One woman received a chemical burn while concentrated acetic acid was being administered. Prescription errors accounted for 60 per cent of all the incidents, compared with 50 per cent for the last three quarters of 1995. The most common prescription errors were: wrong dosage (25 per cent), unclear instruction (27 per cent) and wrong drug name (12 per cent). The Medication Incidents Reporting Programme is voluntary, so the actual number of blunders could be much higher, Michael Ling Ho-ming, president of the Society of Hospital Pharmacy Workers, said yesterday. 'I'm not saying it's acceptable, but you cannot 100 per cent prevent it. I would like to make it [reporting medication incidents] compulsory, but if you do that people are going to hide it,' he said. Almost one-third of the blunders documented in the first quarter of last year were attributed to distraction and stress. The Public Doctors Association president, Dr Andrew Yip Wai-chun, said limited manpower was a powerful factor. 'We are treating a huge number of patients with limited manpower: it's understandable things like this happen,' he said. 'It's related to life and death: the Hospital Authority should look at the reason why this is happening.' In the second quarter, the biggest cause of medication incidents was given as non-compliance with procedures.