Diseases & conditions

Study: Ketamine Has No Clear Benefit for Chronic Pain

Published AUG 18 2025

Story

Image credit: RJ Sangosti/MediaNews Group/The Denver Post/Getty Images

The Facts

A new Cochrane review examined 67 trials involving over 2,300 adult participants to assess the efficacy of five N-methyl-D-aspartate (NMDA) receptor antagonists — ketamine, memantine, dextromethorphan, amantadine, and magnesium — for treating chronic pain.
UNSW Sydney
News Medical
The review, published Monday, found no clear evidence of benefit for ketamine in chronic pain treatment and identified an increased risk of adverse effects such as delusions, delirium, paranoia, nausea and vomiting.
EuroNews
News Medical
Cochrane Library
Evidence quality was rated as low to very low certainty due to small study sizes and poor methodological quality, with researchers noting significant uncertainty about the effectiveness of ketamine.
EurekAlert!
UNSW Sydney
The analysis included various dosing strategies, including intravenous, oral and topical ketamine administration across multiple chronic pain conditions, but found no clear evidence of benefit in any specific condition or dose.
Cochrane Library
UNSW Sydney
No studies in the review reported on whether ketamine reduced depressive symptoms or opioid use, despite ketamine often being proposed for patients with depressive symptoms or opioid tolerance.
EurekAlert!
News Medical
Researchers warned against rushing into widespread ketamine use without strong evidence — drawing parallels to past mistakes with opioid medications that were developed for acute pain but applied to chronic conditions.
EuroNews
UNSW Sydney

Sources Split

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The Spin

Narrative A

The widespread off-label use of ketamine for chronic pain lacks scientific backing and poses real risks to patients. This comprehensive review shows that ketamine doesn't deliver meaningful pain relief while causing distressing side effects like delusions and paranoia. Despite ketamine being proposed to reduce depressive symptoms or opioid use in chronic pain patients, none of the studies reviewed reported on these outcomes, suggesting that ketamine should be avoided.

Cochrane Library

EuroNews

Narrative B

The evidence isn't strong enough to definitively rule out ketamine's potential benefits for chronic pain sufferers. While current evidence for ketamine in chronic pain is uncertain, it shows potential. Some patients report relief, and ketamine's unique action on NMDA receptors offers a novel approach. With better-designed studies, ketamine might become a valuable alternative to opioids. This review should spark more research — not halt exploration of its therapeutic possibilities.

Onlinelibrary

Healthline

Metaculus Prediction

Editor's Note

This story currently has limited coverage. We will continue to monitor all major outlets and update our reporting as additional information becomes available.