Introduction: The epidemic of prescription opioid overdose and mortality parallels the dispensing rates of prescription opioids, and the availability of increasingly potent opioid analgesics.
Objective: The common assumption that more potent opioid analgesics are associated with higher rates of adverse outcomes has not been adequately substantiated. We compared the rate of serious adverse events among commonly prescribed opioid analgesics of varying potency.
Methods: Serious adverse events (SAEs; defined as death, major medical effect, or hospitalization) resulting from exposure to tablets containing seven opioid analgesics (oxycodone, hydrocodone, morphine, hydromorphone, oxymorphone, tapentadol, and tramadol) captured by the Researched Abuse, Diversion and Addiction-Related Surveillance (RADARS®) System Poison Center Program were evaluated from 2010 through 2016. Rates of SAEs were adjusted for availability through outpatient dispensing data and regressed on morphine milligram equivalents (MME).
Results: There were 19,480 cases of SAE during the 7-year study period. Hydrocodone and oxycodone contributed to 77% of SAE cases. Comparing rates of outcome by relative potency, a hierarchy was observed with hydromorphone (8.02 SAEs/100 kg) and tapentadol (0.27 SAE/100 kg) as the highest and lowest rates, reflecting a 30-fold difference among individual opioid products. SAE rate and potency were related linearly-SAEs increased 2.04 per 100 kg drug dispensed for each 1-unit rise in MME (p = 0.004). Linear regression of SAE/100 kg drug dispensed and drug potency identified that MME comprised 96% of the variation observed. In contrast, potency did not explain variation seen using other study denominators (prescriptions dispensed, dosage units dispensed, and the number of individuals filling a prescription).
Conclusions and relevance: Potency of a prescription opioid analgesic demonstrates a significant, highly positive linear relationship with exposures resulting in SAEs per 100 kg drug dispensed reported to poison centers. Potency should be carefully considered from both individual provider and public health perspectives.