A study published in The Lancet examined ketamine's effectiveness in lowering pain or reducing the need for opioids.
Kane Pryor, MD, study co-author and associate professor of clinical anesthesiology at New York City-based Weill Cornell Medicine, and colleagues followed 627 surgery patients from the U.S., Canada, India and South Korea. All patients received either a placebo, a 0·5 mg/kg ketamine dose or a 1·0 mg/kg ketamine dose either after receiving anesthesia or before surgical incision.
Researchers blinded participants, clinicians and investigators to group assignment. Researchers assessed delirium twice daily for the first three postoperative days.
Here's what they found.
1. There was no difference in delirium between the three groups.
2. Ketamine use resulted in more postoperative hallucinations and nightmares than with the placebo.
3. Adverse events, viewed both individually (p value for each >0·40) and collectively (6·9 percent in placebo, 39·6 percent in 0·5 mg/kg ketamine, and 40·8 percent in 1·0 mg/kg ketamine groups), did not differ between groups.
Researchers concluded, "A single subanesthetic dose of ketamine did not decrease delirium in older adults after major surgery, and might cause harm by inducing negative experiences."