A major scientific review has cast doubt on the use of ketamine as a treatment for chronic pain, warning that current evidence is too weak to support its effectiveness.
Once known largely as a party drug, ketamine has in recent years been repurposed in wellness and medical circles, with clinics across Europe offering it as a potential remedy for depression and long-lasting pain. The anaesthetic has a long history in hospitals, where it is used to sedate patients during surgery and as an emergency painkiller. But despite the growing interest, researchers say its benefits for chronic conditions remain unproven.
The review, conducted by Cochrane, an independent nonprofit research organisation, analysed data from 67 clinical trials involving more than 2,300 participants. The trials tested five drugs that target the N-methyl-D-aspartate (NMDA) receptor, which influences how pain signals are processed in the brain. Alongside ketamine, the review included memantine, dextromethorphan, amantadine, and magnesium.
According to the findings, none of the drugs showed clear or consistent benefits for treating chronic pain conditions such as diabetic nerve pain, fibromyalgia, post-shingles pain, or complex regional pain syndrome.
“We want to be clear – we’re not saying ketamine is ineffective, but there’s a lot of uncertainty,” said Michael Ferraro, one of the study’s authors and a researcher at the University of New South Wales. “The data could point to a benefit or no effect at all. Right now, we just don’t know.”
The analysis also highlighted the risks of ketamine, especially when administered intravenously. Reported side effects included delusions, paranoia, delirium, nausea, and vomiting, which were described as “distressing for many patients.”
Importantly, the review did not examine ketamine’s role in treating depression or its potential as a replacement for opioid painkillers. Researchers warned, however, against extending ketamine’s established short-term use in emergency settings to long-term management of chronic conditions.
“We’ve seen the harm that can come from taking medicines developed for acute pain and applying them to chronic pain – opioids are a prime example,” said James McAuley, a professor at UNSW and co-author of the study. “Now we’re seeing a similar pattern with ketamine. We need to be careful not to rush into widespread use without strong evidence.”
The findings arrive amid a surge of interest in new pain treatments, as doctors and patients seek alternatives to opioids. But for now, the researchers conclude, there is little reliable data to support ketamine as a solution for chronic pain – and more rigorous studies are urgently needed.
