"Dunn et al4 found that risk of drug-related adverse events among individuals treated for chronic noncancer pain with opioids was increased at opioid doses equivalent to 50 mg/d or more of morphine. Our analyses similarly found that the risk of opioid overdose increased when opioid dose was equivalent to 50 mg/d or more of morphine.
"The present study also extended prior research in several important ways. We used a large, national sample of individuals and focused exclusively on opioid overdose deaths. Because the circumstances that lead to overdose death may vary by the condition for which the opioid is prescribed and substance use disorder status, we conducted analyses for subgroups of patients, including those with cancer, acute pain, and substance use disorders.
"The present study also extended the prior research by exploring a novel risk factor, ie, concurrent prescriptions of regularly scheduled and as-needed opioids. We found that those patients who were simultaneously treated with as-needed and regularly scheduled opioids, a strategy for treating pain exacerbations,7,8 did not have a statistically significant increased risk of opioid overdose in adjusted models. Recent treatment guidelines have indicated that the long-term safety of this strategy for pain exacerbation has not been established,5,9 and in the present study we did not find evidence of greater overdose risk associated with this treatment practice after accounting for maximum daily dose and patient characteristics."
Bohnert ASB, Valenstein M, Bair MJ, et al. Association Between Opioid Prescribing Patterns and Opioid Overdose-Related Deaths. JAMA. 2011;305(13):1315–1321. doi:10.1001/jama.2011.370