Review Finds Lack of Evidence Supporting Ketamine for Chronic Pain Treatment

Recent research has cast doubt on the effectiveness of using ketamine for managing chronic pain. A comprehensive review conducted by experts from UNSW Sydney, Neuroscience Research Australia (NeuRA), and Brunel University of London analyzed data from 67 trials involving over 2,300 adults. The focus was on five NMDA receptor antagonists—ketamine, memantine, dextromethorphan, amantadine, and magnesium—commonly investigated for pain relief.

The findings, published in the Cochrane Database of Systematic Reviews, indicate that there is no solid scientific evidence to support ketamine’s benefit in treating chronic pain conditions. Moreover, the review identified risks associated with ketamine use, including adverse effects such as delusions, hallucinations, paranoia, nausea, and vomiting. The certainty of the evidence was rated low to very low, primarily due to small sample sizes and methodological limitations across studies.

Dr. Michael Ferraro, the review's lead author, emphasized the uncertainty surrounding ketamine’s efficacy, stating, "We’re not claiming ketamine is completely ineffective, but the current data cannot confirm its benefits." The review also examined different pain conditions and dosing strategies but found no clear advantages.

Side effects were a significant concern, especially with intravenous administration, with psychotomimetic effects being the most common. Interestingly, the review found a lack of evidence regarding ketamine’s potential to reduce depressive symptoms or opioid usage—areas where it’s often proposed for use.

Professor Neil O’Connell highlighted that despite its widespread use, there is no convincing evidence that ketamine provides meaningful short-term or long-term relief for chronic pain patients. The authors strongly advocate for high-quality clinical trials to better understand ketamine's role and safety.

As alternative treatments become more sought after amid the reduction of opioid prescriptions, caution is urged in adopting ketamine widely. Experts warn against rushing into widespread use without robust evidence, echoing concerns that similar issues have arisen with opioid misuse. The review aims to inform both clinicians and patients about the current state of evidence regarding ketamine for chronic pain, emphasizing the need for further research to determine whether it has any true clinical benefit.

Source: https://medicalxpress.com/news/2025-08-ketamine-chronic-pain-unsupported-evidence.html