Side effects from opioids used for acute pain after emergency department discharge

Opioid side effects are common when treating chronic pain. However, the frequency of opioid side effects has rarely been examined in acute pain conditions, particularly in a post emergency department (ED) setting. The objective of this study was to evaluate the short-term incidence of opioid-induced side effects (constipation, nausea/vomiting, dizziness, drowsiness, sweating, and weakness) in patients discharged from the ED with an opioid prescription.

This is a prospective cohort study of patients aged ≥18 years who visited the ED for an acute pain condition (≤2 weeks) and were discharged with an opioid prescription. Patients completed a 14-day diary assessing daily pain medication use and side effects.

We recruited 386 patients with a median age of 54 years (IQR:43-66); 50% were women. During the 2-week follow-up, 80% of patients consumed opioids. Among the patients who used opioids, 79% (95%CI:75-83) reported side effects compared to 38% (95%CI:27-49) for non-users. Adjusting for age, sex, and pain condition, patients who used opioids were more likely to report constipation (OR:7.5; 95%CI:3.1-17.9), nausea/vomiting (OR:4.1; 95%CI:1.8-9.5), dizziness (OR:5.4; 95%CI: 2.2-13.2), drowsiness (OR:4.6; 95%CI:2.5-8.7), and weakness (OR:4.2; 95%CI:1.6-11.0) compared to non-users. A dose-response trend was observed for constipation but not for the other side effects. Nausea/vomiting (OR:2.0; 95%CI:1.1-3.6) and dizziness (OR:1.9; 95%CI:1.1-3.4) were more often associated with oxycodone than with morphine.

As observed for chronic pain treatment, side effects are highly prevalent during short-term opioid treatment for acute pain. Physicians should inform patients about those side effects and should consider prescribing laxatives.