Oral ketamine for acute postoperative analgesia (OKAPA) trial: A randomized controlled, single center pilot study

• Published in: Journal of clinical anesthesia 2025-01, Vol.100, p.111690, Article 111690
• Main Authors: Dinsmore, Michael, Nijs, Kristof, Plitman, Eric, Al Azazi, Emad, Venkatraghavan, Lashmi, Ladha, Karim, Clarke, Hance
• Format: Article
• Language: English
• Subjects: Administration, Oral; Adolescent; Adult; Aged; Analgesia; Analgesics; Analgesics - administration & dosage; Analgesics - adverse effects; Analgesics, Opioid - administration & dosage; Analgesics, Opioid - adverse effects; Back surgery; Clinical outcomes; Clinical trials; Confidentiality; Decompression, Surgical - adverse effects; Double-Blind Method; Drug dosages; Feasibility Studies; Female; Fruit juices; Hospitals; Humans; Ketamine; Ketamine - administration & dosage; Ketamine - adverse effects; Male; Middle Aged; Morphine; Narcotics; Pain management; Pain Measurement; Pain, Postoperative - drug therapy; Pain, Postoperative - prevention & control; Patients; Pilot Projects; Postoperative period; Prospective Studies; Questionnaires; Side effects; Spinal Fusion - adverse effects; Spine surgery; Substance abuse treatment; Treatment Outcome; Young Adult
• ISSN: 0952-8180; 1873-4529; 1873-4529
• DOI: 10.1016/j.jclinane.2024.111690

Although opioids represent the mainstay of treating surgical pain, their use is associated with significant side effects. There is an urgent need to find new pain relievers with safer side effect profiles. One drug that has been receiving increasing attention is ketamine. By using the oral route of administration, ketamine could potentially be used by patients in a less resource-intensive manner with similar efficacy. This study aims to examine the role of oral ketamine in improving recovery after major spine surgery. A prospective, single-center, double blinded parallel arm, placebo controlled randomized feasibility trial. Toronto Western Hospital (TWH), UHN, Toronto, Canada. Adult patients (aged 18–75) undergoing multi-level lumbar spine decompression and fusion with planned overnight admission in hospital. Study treatment (oral ketamine 30 mg) or matching placebo for three days (nine doses total) or until hospital discharge. The primary outcome was the patient-reported Quality of Recovery-15 score (QoR-15). Secondary outcomes were opioid use, pain intensity, pain interference (PROMIS-pain interference questionnaire), mood (PHQ-9) and, side-effects (Generic Assessment of Side Effects Scale). Data from 35 patients were analyzed, of which 18 patients in the ketamine group and 17 patients in the placebo group. There were no significant differences identified in QoR-15 scores at postoperative days 1,3,7, and 30. There were also no significant differences found in pain intensity scale scores at postoperative days 1, 3, 7, and 30, and PROMIS and PHQ-9 scores at postoperative days 7 and 30. Significantly less oral opioids were used in the ketamine group compared to the placebo group on postoperative day 3 and by postoperative day 7. In addition, patients in the ketamine group spent significantly less days on oral opioids and trended to be discharged from hospital earlier. This pilot study demonstrated that low dose oral ketamine can be safely used as an adjunct in postoperative pain treatment to help reduce opioid consumption after major spine surgery. •Although opioids represent the mainstay of treating surgical pain, their use is associated with significant side effects.•Low dose oral ketamine can be safely used as an adjunct in postoperative pain treatment.•Ketamine can more effectively reduce symptoms of pain hypersensitivity, including allodynia and hyperalgesia.