Patients may be at higher risk of overdose when opioid therapy for pain is discontinued

Study suggests enhanced guidance for opioid prescribing needed to manage pain, reduce risk of overdose

Discontinuing opioids prescribed for chronic pain was associated with increased risk of overdose, according to a new study from the BC Centre on Substance Use and University of British Columbia-Okanagan published today in PLOS Medicine.

In order to better understand associations between discontinuation of prescribed opioid therapy for pain and risk of overdose, researchers conducted a retrospective cohort study of people receiving long-term opioid therapy for pain in B.C. between October 2014 and June 2018. They analyzed the medical histories of 14,037 patients registered with the provincial health insurance client roster in B.C. who had been on opioid therapy for pain for at least 90 days.

Researchers found that discontinuing opioid therapy for chronic pain was associated with increased risk of overdose among people without opioid use disorder (OUD). Yet the association was stronger in those with OUD, including those not receiving opioid agonist therapy (a treatment for OUD) and those receiving opioid agonist therapy. Finally, tapering opioid therapy was associated with decreased risk of overdose in those with OUD who had not received opioid agonist therapy.

There were 827 overdose events measured among all patients. People with OUD experienced about half of these overdose events, despite only comprising 5.1 per cent of the entire patient population studied.

“Given the increased risk of overdose, sudden discontinuation of opioid treatment for chronic pain should be avoided in almost all instances,” said Dr. Mary Clare Kennedy, lead author of the study and Canada Research Chair in substance use policy and practice research. “Enhanced guidance is needed to support prescribers in implementing safe and effective opioid for pain tapering strategies, with particular consideration of opioid use disorder and prescribed opioid agonist therapy status.”

In an effort to reduce opioid-related illness and death, Canada has implemented guidelines recommending that clinicians restrict opioid prescribing for chronic non-cancer pain, which includes a recommendation that prescribers reduce doses and potentially discontinue treatment when patients are on higher doses of prescribed opioids. However, the effects of discontinuing opioid treatments on overdose risk have been understudied.

According to the authors, “These findings point to the need to avoid abrupt discontinuation of opioid treatment for pain and to enhance guidance for prescribers in modifying opioid treatment tapering strategies on the basis of opioid use disorder and opioid agonist therapy status.”

The study had several limitations as the outcome measure did not capture overdose events that did not involve a healthcare encounter or result in death. Additionally, the researchers were unable to determine the source of the drugs involved in overdoses, including whether they were prescribed or obtained illicitly.

While the use of high dose opioids to manage pain can increase the risk of adverse events and length of stay, untreated pain continues to remain an issue for many patients, and finding the balance of managing pain while using opioids as safely as possible remains an ongoing challenge for prescribers.

The Opioid Stewardship Program (OSP) at St. Paul’s Hospital in Vancouver is a systems-level intervention developed to address this ongoing gap in care. Implemented in January 2020, the opioid stewardship clinical team consists of a clinical pharmacy specialist and addiction medicine physician who review and assess patients throughout the hospital and provide recommendations to improve opioid prescribing practices. The program also addresses system-wide prescribing through education and review of hospital policies and order sets.

“We have a responsibility to ensure every opioid prescription written in the hospital setting is as safe and as effective as possible,” says Dr. Seonaid Nolan, a co-author of the PLOS Medicine study, as well as the Head Interdepartmental Division of Addiction Medicine and Physician Lead – Opioid Stewardship Program. “Accordingly, the goal of the Opioid Stewardship Program is to improve opioid prescribing practices at St. Paul’s Hospital to reduce or prevent adverse opioid-related events such as overdose, opioid misuse or addiction, while at the same time improve or maintain adequate pain control.”

In the first two years of operation, the program has offered over 3,000 recommendations for improved opioid prescribing among 1,200 patient encounters – 96 per cent of these recommendations were implemented into clinical practice.

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