Morphine is the reference treatment for severe acute pain in an emergency department. The purpose of this study was to describe and analyse opioid-related ADRs (adverse drug reactions) in a large cohort of emergency department patients, and to identify predictive factors for those ADRs.

In this prospective, observational, pharmaco-epidemiological international cohort study, all patients aged 18years or older who were treated with morphine were enrolled. The study was done in 23 emergency departments in the US and France. Baseline numerical rating scale score and initial and total doses of morphine titration were recorded. Logistic regression analysis was used to study the effects of demographic, clinical and medical history covariates on the occurrence of opioid-induced ADRs within 6h after treatment.

A total of 1128 patients were included over 10months. Median baseline initial pain scores were 8/10 (7–10) versus 3/10 (1–4) after morphine administration. Median titration duration was 10min (IQR, 1–30). The occurrence of opioid-induced ADRs was 25% and 2% were serious. Patients experienced mainly nausea and drowsiness. Medical history of travel sickness (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.01–2.86) and history of nausea or vomiting post morphine (OR, 3.86; 95% CI, 2.29–6.51) were independent predictors of morphine related ADRs.

Serious morphine related ADRs are rare and unpredictable. Prophylactic antiemetic therapy could be proposed to patients with history of travel sickness and history of nausea or vomiting in a postoperative setting or after morphine administration.