Introduction of Tamper-Resistant Formulations of Opioids Has No Effect on Abuse Levels

Tamper-resistant formulations of oxycodone and other opioid tablets does not have a significant effect on the population, according to an Australian study published in The Lancet Psychiatry.

Opioid abuse is at an all-time high in Australia and the United States, the authors noted. Pharmaceutical opioids cause more than 70% of opioid overdose deaths in Australia, with similar rates in the United States. The National Opioid Medication Abuse Deterrence (NOMAD) study collected data during a 5-year period, during which tamper-resistant tablets of controlled-release oxycodone were introduced in Australia. These tablets are unable to be crushed into dust and turn into gel when added to water, making it unable to be snorted or injected.

The NOMAD study analyzed whether tamper-resistant formulation oxycodone created a change in population-level usage of opioids and if there was an increase in abuse of heroin and other pharmaceutical drugs. Although Australia received tamper-resistant formulation oxycodone after the United States, it made for a better analysis of the effects of tamper-resistant formulations.

"It is difficult to attribute positive or negative changes in extra-medical use and opioid-related harm to the introduction of tamper-resistant formulation of controlled-release oxycodone in the USA because of the multitude of government-initiated responses to the pharmaceutical opioid problem that occurred during the same period," the authors explained. In the United States the government introduced tighter controls over access to opioids and criminal sanctions against physicians liberally prescribing opioids and there was also increased public awareness and concern over opioid use. "Despite research highlighting the associations between increased pharmaceutical opioid use and harm in Australia, between 2011 and 2016, no changes occurred in regulatory systems for pharmaceutical opioids, opioid prescription guidelines, limits on doctors’ prescribing of opioids, monitoring of patient or doctor access to opioids, or access to medicines via public subsidy."

Face-to-face interviews were conducted in New South Wales, South Australia, and Tasmania in 3 waves: wave 1 was used as a baseline; wave 2 was approximately 1 month after the introduction of the tamper-resistant formulation; and wave 3 was approximately 1 year after the introduction of the tamper-resistant formulation. The cohort consisted of 606 people who used pharmaceutical opioids at least monthly and regularly tampered with opioids by injecting, snorting, chewing, or smoking. These interviews allowed researchers to recognize patterns of use and tampering, diversion of controlled-release oxycodone and the tamper-resistant formulation to other pharmaceutical opioids, and harm related to substance abuse and injection.

Annual surveys were also given out to those who regularly inject drugs to report trends on abuse and extra-medical use. Around 900 surveys per year were given to people in Australian capital cities.

The results showed that there is no significant effect of the introduction of tamper-resistant formulation oxycodone on the population-level, as opioid abuse continues to increase across Australia. There were, however, significant reductions in injections. No population-level effect on harm related to opioid use was relevant. A reduced amount of sales in higher strength oxycodone was noted by the authors. No effect was recorded on the population-level regarding hospital admissions, emergency department presentations, or ambulance overdose attendance.

Nabarun Dasgupta, PhD, of the Injury Prevention Research Center and Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, wrote in an accompanying commentary: “Drug use has been long recognised to be an interaction between drug, individual-level influences, and social context… The NOMAD study leads us to consider whether abuse deterrence is an inherent property of the drug itself, or its intended effect lies in an interaction with social context.”