Severe pain is a therapeutic emergency that can be life-threatening by its location, its repercussions or the misdiagnosis it can cause.

To investigate the efficacy of analgesia by morphine versus that by low-dose ketamine in severe pain in emergency department.

We conducted a randomized open study. We included patients over 18 years-old who consulted for severe pain defined by numeric rating scale (NRS) ≥6. Patients of M group received a titration of 10 mg morphine while those of LDK group, received a bolus of 30 mg of ketamine. The primary endpoint was obtaining a NRS of less than 4 within 10 minutes.

We included 120 patients, 66 in the M group and 54 in the LDK group. The mean baseline NRS was 8.8 ± 1.3 in the M group and 8.6 ± 1.4 in the LDK group (p₌ 0.7). At 10 minutes, the same number of patients in both groups achieved a NRS less than 4 (p = 0.09). However, the mean NRS was significantly lower in the LDK group (p = 0.008). More adverse effects were noted in the LDK group (p <10-3).

Low-dose ketamine appears to be non-inferior to morphine in achieving effective analgesia for severe pain in the emergency department.