- There is good evidence that perioperative ketamine decreases postoperative pain scores and opioid requirements, but there is a lack of consensus on dose, for both bolus and infusion.
- Despite limited evidence, a trial of low-dose intravenous or subcutaneous ketamine adjuvant to morphine may be warranted in refractory cancer pain.
- There is only very limited evidence for the use of ketamine in chronic noncancer pain and concerns and a lack of safety data concerning long-term or repeated treatment. Importantly, there is no strong evidence to support the current practice of treating chronic noncancer pain with repeated intravenous infusions.
- Ketamine has dose-dependent adverse effects, and there are good arguments for avoiding high doses.
- Spinal administration is associated with neurotoxicity, whereas oral ketamine has low bioavailability and is associated with adverse effects.