Ketamine and postoperative pain – a quantitative systematic review of randomised trials
Pain December 15, 2004 Nadia Elia, Martin R. Tramèr 564 citations
Ketamine, an NMDA receptor antagonist, reduces postoperative pain and opioid use but carries a risk of hallucinations. In a systematic review of 53 trials (2839 patients), prophylactic intravenous ketamine (median 0.4 mg/kg) lowered pain intensity on a 0–10 scale by 0.89 cm at 6 hours, 0.42 at 12 hours, 0.35 at 24 hours, and 0.27 at 48 hours, and reduced 24-hour morphine consumption by 15.7 mg, without affecting morphine-related adverse effects. Awake or sedated patients receiving ketamine without benzodiazepine had a 2.32 times higher odds of hallucinations (number needed to harm 21). Under general anesthesia, hallucination risk was low regardless of benzodiazepine use. The overall role of ketamine in perioperative analgesia remains unclear.