LAUSR

OBJECTIVE To compare naloxone doses and clinical outcomes after emergency opioid reversal in opioid-naïve and opi-oid-tolerant inpatients. DESIGN Cross-sectional, retrospective chart review. SETTING Comprehensive cancer center. PATIENTS In-patients who received ≥1 dose of intravenous naloxone for emergency opioid reversal between 2014 and 2018. METHODS Patients were classified as opioid-tolerant based on opioid dosing history ≥60 morphine milligram equivalents/day for ≥7 consecutive days prior to naloxone administration. Response to naloxone was based on documentation of improvement in respiratory rate to >10 breaths/min or improved response to stimuli. OUTCOMES Naloxone doses and clinical outcomes after naloxone administration. RESULTS Ninety-three naloxone episodes (58 opioid-naive and 35 opioid-tolerant) in 80 unique patients were included. No differences between opioid-naïve and opioid-tolerant groups were found for naloxone mean starting doses (0.14 mg vs 0.19 mg, p = 0.35), total doses (0.50 mg vs 0.32 mg, p = 0.07), and response rates (74.1 percent vs 77.1 percent, p = 0.81). Naloxone adverse reactions were more frequent in the opioid-tolerant group than the opioid-naïve group (opioid withdrawal symptoms (OWSs): 14.3 percent vs 0 percent; increase in pain: 20 percent vs 8.6 percent, p = 0.002). CONCLUSIONS In opioid-tolerant patients, naloxone total doses required and response rates were similar to opioid-naïve patients. Use of opioid dosing history to identify potentially opioid-dependent patients should be considered prior to naloxone administration to guide dosing and reduce the risk for precipitating OWSs.