Ketamine vs. Morphine for Analgesia

Interest in ketamine as an analgesic has been growing. To evaluate the analgesic effect and safety of ketamine in an emergency department (ED) setting, investigators conducted a randomized, controlled, double-blind trial involving 90 ED patients with acute abdominal, flank, or musculoskeletal pain.

Patients were treated with subdissociative-dose intravenous ketamine (0.3 mg/kg) or morphine (0.1 mg/kg). Fentanyl was provided as a rescue medication for those requiring additional pain relief. Pain scores and adverse effects were recorded at 15, 30, 60, 90, and 120 minutes.

Pain relief at 30 minutes (the primary outcome) was similar with ketamine or morphine. Rescue fentanyl was used as frequently with each drug at 30 and 60 minutes but was required by 17% more ketamine recipients than morphine recipients at 120 minutes. More ketamine than morphine recipients reported adverse effects — including dizziness, disorientation, mood changes, and nausea — at 15 minutes (69% vs. 31%), but not at 30 minutes. All adverse effects were transient; none required treatment.