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.