Not surprisingly, 10 of the most commonly prescribed PBS medicines in 2015–16 were included in the list of the 20 most commonly returned PBS-listed medicines in the 2016 audit. Six of the most commonly returned PBS medicines in 2016 are used for chronic conditions, and three – atorvastatin, simvastatin and metformin – were in the top 20 most prescribed PBS medicines (Table).
In comparing the 2016 and the 2013 RUM Project audit results, 11 PBS-listed medicines appear on both lists (Table). Salbutamol and glyceryl trinitrate appear in the top five of both audits. In 2013, 13 of the most commonly returned PBS medicines were ‘if required’ medicines. These were defined as items used for acute conditions such as nausea, acute infections, asthma or angina attacks, medicines that required regular dose adjustments (e.g. prednisolone, warfarin), and analgesics. Analgesics were included because, although pain can be acute or chronic, there are often dose adjustments and medicine changes for people with chronic pain conditions. The results revealed that in 2016 the top six were ‘if required’, as well as 14 of the 20 most commonly returned PBS-listed medicines.
Just over a third (36%) of all medicines returned in 2016 were expired, compared with 51% in the 2013 audit. Approximately 10% of the PBS-listed medicines were expired and approximately 10% were unopened.
The 2016 audit attempted to calculate a cost to the PBS of wasted medicines. PBS waste was assumed to consist of all dispensed (i.e. had a dispensing label) and unopened PBS-listed medicines, irrespective of expiry. If a medicine had been opened and at least one dose taken, it was not considered as waste as it could have been discarded for valid reasons, including adverse events or poor efficacy. Using this definition, and assuming that the sample was representative of the total number of bins collected annually, the estimated cost of wasted medicines discarded via the RUM Project is approximately $11.6 million a year.