Opioid use on rise in NZ

New research provides evidence of increasing dispensing of opioids in older people and following surgery in New Zealand patients.

Opioids are a class of pain medications with potential for addiction, including codeine, dihydrocodeine, tramadol, and stronger forms, fentanyl, morphine, pethidine, oxycodone.

In the US, addiction to these drugs has reached 'epidemic' levels, leading to a surge in illegal sales, overdoses, and deaths.

“Opioids are commonly prescribed for pain and, while we don’t yet have an epidemic in New Zealand, as in the US, these findings should spark concern,” says Associate Professor Amy Chan of the School of Pharmacy in the University of Auckland. 

One in ten stay on opioids post surgery

One new opioid study looked at persistent use among opioid-naïve patients who underwent surgery and were dispensed opioids after discharge.

Researchers looked at community pharmacy dispensing records for more than 260,000 patients who were admitted to any New Zealand hospital between 2007 and 2019.

They found the overall rate of persistent use to be 9.1 percent. See Anesthesiology and Analgesia.

Persistent opioid use is a common signal of opioid-related harm in research literature, defined as when opioids are used beyond 90 days after an event.

“Risk factors for persistent use included prescriptions of higher opioid doses, multiple types of opioids and changing to different opioids in the first 90 days after discharge,” lead author, pharmacy lecturer, Jiayi Gong says.

Conversely, being prescribed non-opioid pain relief post-surgery was associated with a reduced risk of developing persistent opioid use.

Other risk factors included: surgical specialties (cardiac/neurological), having other serious health conditions, smoking, and pre-operative use of certain medications, notably sedatives and non-opioid pain relief, Gong says.

Trending upwards in older people

Another study from the University looked at health records for more than 800,000 people over 65 years old, from 2007 to 2018, finding steadily increasing opioid prescribing, particularly among women and those over 85 years of age. See Australasian Journal on Ageing.

Hoda Fahmy, of the School of Pharmacy at the University of Auckland, led the research using national health databases with the aim of addressing a gap in knowledge of opioid prescribing in Aotearoa New Zealand.

Fahmy says opioid use in older adults can be problematic.

“Opioid therapy should only be considered when potential benefits are likely to surpass risks, where it should be prescribed with extensive monitoring and regular assessments to determine the need for continuation,” she says.

The researchers found that codeine was the most commonly prescribed opioid, followed by tramadol.

At the time of the study, codeine was allowed to be prescribed for three months’ supply. From October 2023, codeine supply was limited to one month.

Both codeine and tramadol are weak opioids, but co-author Dr Chan says weak opioids are still a cause for concern, especially in older adults.

“Weak opioids can still lead to dependency and carry additional risks for older people who are more susceptible to side effects, as their kidney function is often reduced and it is important for processing these medicines,” Chan says

Fentanyl was the drug that showed the greatest increase over the study period, which Fahmy says probably relates to the fact funding for fentanyl patches became unrestricted in February 2011.

“Future research is warranted to discern whether the increase in opioid dispensing is a consequence of overprescribing or reflects appropriate pain management practices and to establish evidence-based guidelines for the use of opioids in the older population,” Fahmy says.

Fahmy conducted the research as part of her master’s and contributing to a suite of studies looking at dispensing of opioids in different groups and associated harms.

The increasing prescription of opioids in older adults should continue to be monitored further and inform policies and prescribing, Fahmy says.

A related study involving a sample of almost 270,000 opioid-naïve older adults without a cancer diagnosis investigated risk factors for persistent opioid use.

The strongest risk factors included: use of fentanyl, slow-release opioids, strong opioids, multiple health issues, history of substance abuse, residing in the most socioeconomically deprived areas, and the use of medications like anti-epileptics, non-opioid pain medications, antipsychotics, or antidepressants. See Age and Ageing.

These findings, which augment our understanding of rising prescription rates, underscore the need for targeted interventions to prevent persistent opioid use and its associated adverse outcomes, says Assistant Professor Kebede Beyene, Hoda’s primary masters supervisor.

“The findings from both studies emphasise the importance of precise opioid management for older people, aiming to optimize treatment while minimising risks,” says Beyene.

Chan suggests that individuals and families should keep an eye on opioid use and seek a medication review for long-term use. She also calls for cautious prescribing and policy vigilance regarding opioid supply.

Future research out of the School of Pharmacy will look at opioid prescription in rest homes and the social and economic impacts of opioid use, especially as more up-to-date data become available.

US warns NZ high risk for illegal fentanyl trade

The University research comes as a United States Government-backed briefing highlighted New Zealand as a country with a high risk emerging of fentanyl abuse.

Dr Vanda Felbab-Brown, Senior Fellow of Foreign Policy at the Brookings Institution’s Strobe Talbott Center for Security, Strategy and Technology told a press briefing on the United States fentanyl crisis that New Zealand and Australia are highly valuable markets where existing drug networks provide ample opportunities for the spread of synthetic opioids. See 1News 16 February.

US Secretary of State Antony Blinken has called for greater international cooperation to fight synthetic drugs, like fentanyl, while Colombia has announced its support for a public health-focused approach to the global drug trade.

Blinken and Colombian President Gustavo Petro were speaking at the UN Commission on Narcotic Drugs in Vienna in March 2024.