Opioids: did PBS restrictions reduce use in Australia?
Subsidised opioid use has dropped overall, but use of one opioid is still on the rise, reveals a new study published by UNSW Sydney.
The Pharmaceutical Benefits Scheme (PBS) introduced changes to the supply of prescription opioids in June 2020 with an aim to reduce the amount of these drugs in the community and cut the number of unnecessary prescriptions.
Aligned with changes made by Australia’s medicines regulator, the Therapeutic Goods Administration (TGA), the PBS-related changes involved restrictions on the number of repeat prescriptions, introduction of half-pack sizes and increased level of authorisation for prescribing some opioids amongst others.
The big health data study by the UNSW, published in the Medical Journal of Australia, shows the tightened PBS restrictions led to a drop in PBS subsidised opioid use — and are likely to have reduced all prescription opioid use in Australia. The one exception was the newest opioid medicine, tapentadol.
Supply before and after the policy changes
“Opioid use subsidised through the PBS declined as a result of all these changes, and that likely represents a true decline in opioid use,” says study co-senior author Dr Benjamin Daniels, a Senior Research Fellow and Cancer Institute NSW Early Career Fellow from UNSW’s Medicines Intelligence Research Program.
“Our study indicated that some people chose to access opioids using unsubsidised private prescriptions, meaning they weren’t bound by the new PBS rules, but this wasn’t extensive.”
The research team used two data collections to reach their findings: national PBS dispensing records and national wholesale data on sales to community pharmacies in Australia. PBS data provided information on how PBS-subsidised opioid medicines were used, while the sales data provided information on total prescription use across the country — both PBS and private sales.
The researchers examined the changes in opioid supply in the two years before and one year after the policy change, using a standard metric — oral morphine equivalent milligrams (OMEs) — that accounts for opioid strength. Different opioid medicines contain different potency levels — for example, the opioid codeine has lower OMEs compared to stronger opioids like oxycodone or fentanyl.
“We found an overall 4% decline in OMEs dispensed through the PBS in the year after the policy changes,” Daniels said.
“On face value this doesn’t sound like a big change, but it equates to around 9000 20-tablet packets of 30 mg combined codeine-paracetamol formulations or 4000 fewer 20-capsule packets of 50 mg tramadol dispensed annually.”
Instant release formulations — that is, opioids that provide faster but shorter-term pain relief compared to controlled release formulations — were the main contributors to this decrease.
The PBS changes included tightening restrictions around prescribers’ ability to write repeat prescriptions for these medicines. The team found the number of repeat prescriptions fell from 7.4% of all opioid dispensings pre-June 2020 to 1.3% after the PBS changes. This change was largely driven by codeine/paracetamol combinations and tramadol.
Most opioids, including controlled-release formulations, saw decreases in use through the PBS following the changes.
“The use of most opioids has been declining over the past five or so years, but tapentadol has been going in the other direction during that time,” Daniels said. Tapentadol was listed on the PBS in 2014 and it’s common for the use of newer medicines to increase until the market has matured, the researchers say.
“When these changes to the PBS came into effect, that upward trajectory levelled off on the PBS, but sales of instant-release formulations — which aren’t available through the PBS — jumped up by over 9%.”
The team suspect that COVID-19 may help explain this jump, given the temporary ban on elective surgeries decreased opioid sales between March and May in 2020, but more research is needed explain the shift.
A complex issue
Daniels said the overall decline in opioid use is positive news. Opioids are currently the leading cause of drug-induced deaths in Australia, and our country is the ninth-highest per-capita consumer of opioids in the world.
Among people with chronic pain, opioid dependence and misuse is estimated to be 10% and 24%, respectively.
The PBS restrictions were one measure to try to address this issue — but when the changes were announced, they were met with mixed responses from the community.
For many, it led to an extra burden of needing to return to their doctors to get additional prescriptions, while others were driven to the private market to get pain relief.
A 2022 research paper from UNSW’s National Drug and Alcohol Research Centre (NDARC) — based on research before the PBS rules were tightened in 2020 — found that one in three chronic pain sufferers have difficulty getting ongoing opioid prescriptions.
“While our study gives us a high-level look at what happened following the changes, we don’t see how individuals are impacted,” Daniels said.
“Balancing harms and benefits can be very challenging for medicines like opioids. There are a lot of people who benefit from these medicines, and they carry with them high risks of misuse and harm.”
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