When It Comes to Opioid Overdose, Does Duration of Action Matter?

Prescribing short-acting narcotic painkillers to patients lessens their chance of unintentional overdose in the first few weeks of therapy, according to a new study that was the first to address the relationship between risk of overdose and an opioid’s duration of action.

The illegal selling of prescription opioids is a major concern that has contributed to skyrocketing rates of unintentional and intentional opioid overdoses in recent years, noted the researchers. Has prescribing narcotics to manage moderate to severe pain contributed to the problem? If so, are some regimens safer than others? To find out, the researchers examined the relationship between narcotic prescription use and nonfatal overdoses among more than 840,000 who filled analgesic short- and long-acting opioid monotherapy prescriptions between January 2000 and December 2009.

According to the study, 17.5% of the nearly 19,000 patients who received long-acting opioids were new users of the drugs and were often prescribed hydrocodone at higher daily doses than the more than 800,000 patients who received short-acting agents.

A total of 319 unintentional overdoses occurred: 282 in patients on short-acting opioids and 37 among patients on long-acting agents. Patients on long-acting painkillers were overall 2.5 times more likely to overdose and 5 times more likely to overdose in the first 2 weeks of therapy than patients on short-acting agents. Additionally, patients who took opioid doses greater than 50-mg equivalents of morphine were more than twice as likely to overdose than patients prescribed 1- to 20-mg equivalents, noted the study.

The researchers attributed the significant increased risk of overdose among patients on long-acting opioids to misuse of the drugs, not to an exceptionally low rate of injury among short-acting opioid users.

They conceded that the findings did not account for substance use disorders and physical and psychiatric illness that could have impacted overdose rates. In addition, opioid adherence was not measured directly and some overdoses that occurred during the study period may have gone unreported. Finally, the results were obtained from older, mostly male patients battling chronic pain and can’t necessarily be applied to women and patients without chronic medical conditions.

Despite these limitations — and unlike the designs and small patient populations of previous clinical trials that made it difficult to extract meaningful conclusions about the dangers associated with varying lengths of continuous opioid use — the current findings provided the “first evidence that the risk of unintentional opioid overdose injury is related to the prescribed drug’s duration of action,” noted the researchers.

They suggested that the daily dose and duration of action must be considered when prescribing narcotics and favored the use of “short-acting opioids whenever possible, especially during the first 2 weeks after initiation of therapy.”

The study was published online in JAMA Internal Medicine.

—Dan Cook

Reference:

1. Miller M, Barber CW, Leatherman S, et al. Prescription opioid duration of action and the risk of unintentional overdose among patients receiving opioid therapy. JAMA Intern Med. 2015 Feb 16. [Epub ahead of print]