'Drugs unused are like guns in the broom cupboard' says Dr Myles Conroy.
Too many Australians are being sent home from hospital with large amounts of powerful painkillers, putting them and others at risk of addiction and unintentional overdose, doctors say.
There are also fears careless prescribing by hospital staff is fuelling the thriving black market for prescription opioids in Victoria, where about 300 people die from medication overdoses each year - more than the state's road toll.
Myles Conroy, a pain clinician at Geelong Hospital, said a study of 334 patients' at his hospital in 2011 revealed scores were being sent home after surgery with either too much or too little pain medication, and in some cases an inappropriate drug for their pain. He said the analysis, which looked at the painkillers people were being given on the day before their discharge and then to take home, showed about one in four of the 178 patients who were given opioids on discharge did not require them.
In most cases, they were being given boxes containing 20 to 28 Oxycodone and Oxycontin tablets - opioids dubbed ''hillbilly heroin'' because of their desirability among drug abusers who will pay $10 to $50 for a tablet.
Dr Conroy said this meant patients were at risk of taking the drugs unnecessarily and developing an addiction or passing the drugs on to others who may already have a dependency or could develop one. The drugs were also a major risk for people with children who could accidentally swallow them.
''They are not drugs we want to be spraying around when they are not required,'' he said. ''We think that drugs that are unused are like guns in the broom cupboard. They are just a danger you don't need.''
Dr Conroy said the analysis also revealed that about one third of people requiring opioids for their pain on the day before their discharge had them ceased when they went home. This also occurred for three-quarters of the patients on anti-inflammatory drugs such as Voltaren and Celebrex in hospital, meaning many patients were likely to have untreated pain at home and require another visit to a doctor for a script. In most cases, junior doctors with little experience in pain medicine were making the prescription decisions.
''There is evidence of under treatment and over treatment just through not taking enough care and individualising the treatment for patients,'' he said. ''Education is the key. We need to get junior doctors to understand the gravity of the situation.''
Brendan Moore, the immediate past dean of the faculty of pain medicine at the Australian and New Zealand College of Anaesthetists, said the study suggested many Australian hospitals would be sending opioid drugs ''out by the truckload into society''.
He said more work should be done to understand people's needs, and in some cases, doctors should consider giving patients a smaller number of tablets to take home.
''If you present someone with 20 tablets, there's almost an implied expectation that they might get at least a third or halfway through the box. ''
A spokesman for the Victorian department of health said the government was working on strategies to improve opioid prescribing in hospitals, but did not provide further detail.