Post-op Rx for Opiates and Subsequent Abuse

February 22, 2018

Written by Alex Chen, MD

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Total duration of opioid use was the strongest predictor of misuse. Each refill and additional week of opioid use increased the hazard of misuse by 44% and 19.9% respectively. Shorter prescriptions (<2 weeks) of high vs low dosage prescriptions had a lower hazard.

Why does this matter?
The authors cite that age adjusted rates of opioid overdose have tripled, placing it as the leading cause of death related to unintentional injury. Surgical patients are nearly four times more likely to get opioids compared to their non-surgical counterparts. This study attempts to provide more information to guide post-surgical opioid prescriptions.

Whose fault is it anyway?
This was a retrospective cohort study which looked at 1,015,116 opioid naïve patients undergoing surgery. They defined opiate naïve as patients that had ≤7d of opioid use in the 60d prior to surgery. Importantly, out of the 4.7 million surgical patients originally assessed, approximately 3 million patients were excluded due to either lack of medical insurance or prescription insurance prior to the surgery with an additional 700k excluded due to lack of post-surgical medical insurance and prescription coverage. This left out a large population that was particularly vulnerable.

Rate of misuse increased from 145 cases per 100,000 person years to 293 per 100,000 person years with a single refill compared to none. Each additional refill increased the hazard of misuse by 44% (CI 40.8-47.2%). Each additional week of opioid use was associated with an increase in hazard of 19.9% (CI 18.5-21.4%). This was in contrast to dosage prescribed, which increased hazard by 0.8% for each additional 10 morphine mg equivalents/day. This only applied to shorter durations of prescriptions (<90d).

Interestingly, this study found that the trend of opioid prescribing habits has shifted towards increasing durations of prescriptions with lower doses of opioids. These results imply that we are going in the wrong direction and optimal post-operative analgesia may lie in moderate to higher doses for shorter durations.

Source
Postsurgical prescriptions for opioid naive patients and association with overdose and misuse: retrospective cohort study.  BMJ. 2018 Jan 17;360:j5790. doi: 10.1136/bmj.j5790.

Reviewed by Clay Smith.