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

Canada and the United States have implemented guidelines to restrict opioid prescribing for chronic pain in an effort to reduce opioid-related illness and death. However, the effects of discontinuing opioid treatments on overdose risk are understudied. 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 British Columbia between October 2014 and June 2018. They analyzed the medical histories of 14,037 patients registered with the provincial health insurance client roster in British Columbia who had been on opioid therapy for at least 90 days.

The researchers found that discontinuing opioid therapy for pain was associated with increased overdose risk among people without opioid use disorder (OUD). Yet the association was stronger in those with OUD, including those not receiving opioid agonist therapy (AHR = 3.18; 95% CI = 1.87 -- 5.40, p<0.001) and receiving opioid agonist therapy (AHR = 2.52; 95% CI = 1.68 -- 3.78, p<0.001). Finally, tapering opioid therapy was associated with decreased risk of overdose in those with OUD who had not received opioid agonist therapy (AHR = 0.31, 95% CI = 0.14 -- 0.67, p=0.003).

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 and whether they were prescribed or obtained illicitly.

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."

Kennedy adds, "Given the increased risk of overdose, sudden discontinuation of opioid treatment for chronic pain should be avoided in almost all instances. 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."