Two-Thirds of Prescribed ER Opioids Go Unused, Adding to Risk of Misuse: Study

Prescription opioid pain medication is seen on Sept. 12, 2023, in Chelsea, Quebec. (The Canadian Press/Adrian Wyld)

Many patients with acute pain discharged from emergency departments with opioid prescriptions end up not using them, potentially contributing to later misuse and opioid overdose, according to a recent study.

The study, published in the Canadian Medical Association Journal on July 15, found that participants consumed a median of only five tablets out of a total prescription of 16 tablets, with most stopping opioid use within 2 weeks. That left nearly two-thirds of the opioids unused and potentially available for misuse.

The study aimed to determine the optimal quantity of opioids to prescribe to patients with acute pain at emergency department discharge, in order to manage pain while minimizing the amount left unused.

Canada is grappling with an opioid crisis, with 44,500 deaths due to opioid toxicity occurring since 2016,  according to government data.

In 2023, Canada recorded 8,049 apparent opioid toxicity deaths, marking a seven percent rise from 2022, according to the Public Health Agency of Canada. On average, this equates to 22 deaths per day.

The researchers—Dr. Raoul Daoust of Montreal’s Sacré-Coeur Hospital and his co-authors— surveyed 2,240 adults in Ontario and Quebec suffering acute pain lasting less than two weeks. The participants had been  discharged from emergency departments with an opioid prescription.

During the study, patients were instructed to maintain a diary for a 14-day follow-up period. They recorded whether they had filled their initial prescription, the amount of opioids consumed (converted to 5 mg morphine per tablet for comparison), and whether they had obtained any additional prescriptions.

Additionally, researchers noted that the amount of opioids taken varied greatly between conditions. To meet the opioid needs of 80 percent of patients for two weeks, those with renal colic required just eight tablets—less than those with neck pain (17 tablets), back pain (21 tablets), and fractures (24 tablets).

Splitting Prescriptions

Researchers said that while opioids prescribed in emergency departments constitute a relatively small proportion of the quantity prescribed each year, they found about half of patients with opioid use disorder reported their initial exposure to opioids was through a legitimate prescription, with nearly 20 percent of these prescriptions originating from emergency department visits.

Approximately 80 percent of individuals who misuse prescription opioids have a prior substance use disorder, and 93 percent have a history of using psychoactive drugs before their initial exposure to opioids, the study noted.

To avoid misuse of prescriptive opioids, the authors suggested a strategy where pharmacists initially dispense half of the prescribed amount to patients and instruct them to return for the remainder if needed. The prescription would have an expiration date of two weeks.

“Our findings may provide guidance to enable clinicians to prescribe lower quantities of opioids and provide them in even smaller portions tailored to the specific cause of acute pain, thereby allowing adequate pain relief while reducing the risk of opioid misuse,” researchers wrote.

The researchers recognized the need for future studies to explore the balance between limiting unused opioids and managing patient inconvenience. They said that splitting prescriptions into smaller portions could be a potential burden for patients and adds to the cost of pharmacist services.