Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Ketamine may spur hallucinations and nightmares in older patients

  • Comment

The drug ketamine does not lower levels of pain or reduce the need for pain-killing opioid drugs in the days after an operation, according to US researchers.

They noted that anaesthetists often give patients low doses of the drug during operations, with recent studies even suggesting it might alleviate post-surgical delirium and confusion in older adults.

“We were particularly surprised by the lack of an effect on post-operative pain”

George Mashour

However, in their study, published in The Lancet, indicated that the drug achieved none of these benefits.

Furthermore, they noted that older surgery patients who received ketamine during surgery were more likely to experience hallucinations and nightmares.

The researchers followed 672 surgery patients in four countries – the US, Canada, India and South Korea – who were all at least 60 years old.

During surgery, the patients either received no ketamine, a very low dose of the drug, or a slightly higher dose – matching those routinely given to surgery patients by anaesthetists.

The patients were then evaluated for several days after surgery. Researchers asked about pain, kept track of the amount of opioids needed to control it, and evaluated them twice daily for delirium.

“There’s been a big increase in the amount of ketamine given in the operating room”

Michael Avidan

Lead author Professor Michael Avidan, from Washington University, said: “In recent years, there’s been a big increase in the amount of ketamine given in the operating room because clinicians are trying to prevent pain after surgery without relying on opioid drugs.

“We found that the current practice of giving low doses of ketamine to patients during surgery is not having the desired effect,” he said. “So we need to determine whether higher doses might be more effective, or we need to find other alternatives to opioids.”

Professor Avidan added that because the study had the same results at different sites in different countries made him confident that the way ketamine was being used during surgery was not having the desired effect on delirium and post-operative pain.

“While not helping with those things, ketamine was causing other problems for patients, such as an increase in hallucinations and nightmares,” he added.

Study co-author Professor George Mashour, from the University of Michigan, said: “Overall, patients who develop delirium have worse outcomes and are at higher risk for long-term cognitive decline. So it’s really important to try to prevent it if we can.

“We were particularly surprised by the lack of an effect on post-operative pain,” he added.

  • Comment

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Links may be included in your comments but HTML is not permitted.