Rapid dose escalation of ketamine to 500 mg does not appear to be beneficial for cancer pain and may come with serious adverse events, according to an updated Cochrane review involving 3 trials. Among the findings:

• 2 studies showed that the addition of ketamine to reduced pain intensity and morphine requirements.
• The third study—which used high doses of ketamine—showed no benefit of adding ketamine to different opioids.
• Increased doses of ketamine caused side effects such as hallucinations in some.

The reviewers noted that the findings are based on poorly-designed studies with small numbers, making the evidence very low quality.