High Opioid Doses, Naloxone, and Central Nervous System Active Medications Received by Medicare-enrolled Adults

Background: A limited number of studies have analyzed prescribing among Medicare-enrolled adults at risk for opioid overdoses. The objectives of this study were to evaluate prescribing for naloxone and central nervous system (CNS) active medications and to determine the relationships of patient characteristics with exposure to these medications.

Methods: This was a retrospective cross-sectional analysis of a Medicare-enrolled medication therapy management eligible cohort. Patients were stratified into two cohorts, individuals with a mean daily morphine milligram equivalent (MME) dose <50 and individuals with MME ≥50. Medications assessed included benzodiazepines, skeletal muscle relaxants (SMR), hypnotics, gabapentanoids, selective-serotonin reuptake inhibitors (SSRI), serotonin-norepinephrine reuptake inhibitors (SNRI), tricyclic antidepressants (TCA), antipsychotics, barbiturates, other antiepileptics, hydroxyzine, and naloxone. Chi-square with odds ratios and logistic regressions determined the relationships of medications and patient characteristics with mean daily MME ≥50. Relationship between medications and opioid dose was adjusted for age and sex.

Results: There were 3452 patients with a daily MME <50 and 1116 with a daily MME ≥50. After adjusting for age and sex, patients with a daily MME ≥50 were more likely to be prescribed hypnotics (OR: 1.41, 95% CI 1.17-1.70), SNRIs (OR: 1.39, 95% CI 1.17-1.64), and naloxone (OR: 3.21, 95% CI 2.49-4.12) (p < 0.001). Nine percent of eligible patients received naloxone. Age groups of persons <85 years of age had 1.58-4.04 (p ≤ 0.004) times the odds of being prescribed a mean daily MME ≥50.

Conclusion: Nearly one-fourth of patients were prescribed a mean daily opioid therapy of MME ≥50. These patients were more likely to be prescribed hypnotics, SNRIs, and naloxone. Patients receiving chronic high-dose opioid therapy were more likely to be in age groups of persons <85 years. Naloxone may be underprescribed among eligible adults. Targeted medication services may ensure optimal prescribing among Medicare patients with chronic opioid therapies.