Objective
Emergency physicians have become hesitant to treat patients with opioids because of downstream sequelae related to opioid use disorder. We enrolled a prospective cohort to determine whether the experience of a patient receiving an intravenous (IV) opioid was associated with multiple opioid prescriptions. Specifically, we tested whether greater improvements in pain and a larger euphoric response could predict which previously opioid-naive patients exposed to IV opioids would fill at least two opioid prescriptions in the subsequent 6 months. Methods We recorded pain scores (range, 0–10) before and 15 minutes after opioid-naive emergency department patients were given IV opioids to manage severe pain. We also determined opioid-induced euphoria (range, 0–10 points) by querying how good, how high, how much euphoria the opioid caused, and how likely the participant was to want the opioid again. Sixmonth outcomes were ascertained using the state prescription monitoring database. Results Among 506 patients, 32 (6.3%) filled at least two prescriptions during the 6 months following the emergency department visit. TThere were no differences between those who filled ≥2 prescriptions and those who did not with regard to pain relief (P=0.54), how good the medication made participants feel (P=0.91), how high the medication made participants feel (P=0.97), how much euphoria the opioid caused (P=0.23), or how likely the participant was to want the medication again (P=0.37). Conclusion Filling at least two opioid prescriptions was uncommon after initial exposure to therapeutic IV opioids and was unrelated to either analgesic efficacy or opioid-induced euphoria.

Objective
Individual experience with opioids is highly variable. Some patients with acute pain do not experience pain relief with opioids, and many report no euphoria or dysphoric reactions. In this study, we describe the clinical phenotypes of patients who receive intravenous opioids.
Methods
This was an emergency department-based study in which we enrolled patients who received an intravenous opioid. We collected 0 to 10 pain scores prior to opioid administration and 15 minutes after. We also used 0 to 10 instruments to determine how high and how much euphoria the patient felt after receipt of the opioid. Using a cutoff point of ≥50% improvement in pain and the median score on the high and euphoria scales, we assigned each participant to one of the following clinical phenotypes: pain relief with feeling high or euphoria, pain relief without feeling high or euphoria, inadequate relief with feeling high or euphoria, and inadequate relief without feeling high or euphoria.
Results
A total of 713 patients were enrolled, 409 (57%) of whom reported not feeling high, and 465 (65%) reported no feeling of euphoria. Median percent improvement in pain was 37.5% (interquartile range, 12.5%–60.0%). One hundred seventy-eight participants (25%) were classified as experiencing pain relief with euphoria or feeling high, 190 (27%) experienced inadequate relief with euphoria or feeling high, 101 (14%) experienced pain relief without euphoria or feeling high, and 244 (34%) reported inadequate relief without euphoria or feeling high.
Conclusion
Among patients who receive intravenous opioids in the emergency department, the experiences of pain relief and euphoria are highly variable. For many, pain relief is independent of feeling high.