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Addiction specialists call tamper-resistant opioid formulations a 'gimmick'

06/29/2015 02:13 EDT | Updated 06/29/2016 05:59 EDT
TORONTO - Tamper-resistant opioid formulations that are meant to discourage illicit use of the powerful painkillers are a "gimmick" and don't address the problems of over-prescribing, addiction and overdose deaths, says a commentary published Monday in the Canadian Medical Association Journal.

Among the tamper-resistant opioids is OxyNeo, a re-formulation of OxyContin approved in Canada in 2011 and designed to make it difficult for non-medicinal users to crush the pill so it could be snorted or prepared for injection to achieve a quicker and more potent high.

But the new formulation doesn't prevent illicit users from simply ingesting OxyNeo, which like other opioids carries a risk of addiction and overdose when taken in excessive amounts.

"When you use a tamper-resistant opioid, you're still getting the full effect of the opioid and you don't necessarily have to tamper with the medication to have harm," said Dr. Pamela Leece, a resident in the University of Toronto's public health and preventive medicine program, who co-authored the CMAJ commentary.

"The main issue is that all opioids are unsafe," she said. "There's definitely a role for them in chronic pain and cancer pain, but they're among the most dangerous drugs that we prescribe.

"So even though these new formulations can have some tamper-resistant features to them, they should not be considered safe."

Canada and the U.S. are the highest per-capita users of narcotics in the world. Oxycodone prescriptions in Ontario rose 850 per cent between 1991 and 2007. A study published last July found the annual rate of opioid-related overdose deaths in Ontario alone jumped to 550 in 2010 from 127 in 1991.

While some research suggests that tamper-resistant formulations of oxycodone may have reduced illicit use of the medication, there is growing evidence that the overall number of opioid deaths has not decreased.

That's because those who are addicted to the potent narcotics will simply favour other types of opioids — such as fentanyl patches or hydromorphone — or switch to heroin, all of which can cause fatal overdoses.

"So to focus on a strategy that just addresses tampering is a minor portion of the problem," said Leece.

On Friday, Health Canada announced it is seeking "stakeholder feedback" on plans to require all oxycodone products to be tamper-resistant, reversing the federal government's earlier decision to allow generic versions of OxyContin to be sold in Canada.

Benedikt Fischer, a senior scientist at the Centre for Addiction and Mental Health in Toronto, said the use of the word "gimmick" to describe tamper-resistant opioid formulations is appropriate and a "neat little punch line."

"It's refreshingly strong language, but I think it points to an important point," said Fischer, commenting on the authors' conclusions.

"The majority of opioid misuse does not involve tampering," he said. "Even if you have tamper-resistant opioids, what happens is some people ... use other opioids that are not tamper-resistant.

"We're seeing that on a grand scale in Canada since the new OxyNeo came in. We've had a decline in the oxycodone prescribing, for sure, but we've had increases in other potent opioid formulations ... That's why we've also seen spikes in deaths using fentanyl and hydromorphone."

Fischer said the advent of tamper-resistant formulations is a bonus for the government because it makes it look as if it is taking some kind of action. "So politically, the symbolism is strong."

For the pharmaceutical industry, manufacturers typically get to sell the updated drugs at a higher price — and with new patent protection that prohibits cheaper generic versions from taking their market share.

"They can come up with new patents and it never gets questioned whether these drugs should be prescribed in the first place or in the amount that they're being prescribed," he said.

"In other words, it relegitimizes the practice."

Opioids are often given for short-term control of acute pain — for instance, following surgery or injury — but many doctors also prescribe them for chronic pain, which is a difficult condition to treat, in part because each patient's level of suffering is different and also subjective.

There's no clear-cut way to decide on how ongoing pain should best be treated, Leece said, especially for busy primary-care doctors who may not have ready access to a pain specialist or allied practitioners like physio and occupational therapists.

"It's easy to write a prescription," despite knowing the potential dangers, she said.

Leece said a broader strategy is needed that encourages physicians to be more careful about prescribing opioids; provides access to comprehensive pain management therapies for patients; and includes a system-wide monitoring of opioids and their subsequent harms, including up-to-date fatal overdose figures.

"So the real action will not be just with switching to a different formulation. It will be from having real leadership and a comprehensive plan to resolve the problem."

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