Ketamine offered no clinical benefit in pain management of cancer
Researchers who conducted a randomized, phase 3 trial designed to evaluate pain management in a cohort of patients with cancer observed no difference between ketamine and placebo.
Ketamine, an anesthetic, often is used to treat cancer-related pain but evidence to support its use in this setting, according to researchers.
The researchers conducted this multisite, double blind, trial to evaluate whether ketamine was more effective for management of chronic uncontrolled pain than placebo when used in conjunction with opioids and standard adjuvant therapy.
Outcome measures included a clinically relevant improvement in pain with limited breakthrough analgesia and an acceptable toxicity profile.
The trial included 185 participants. They were randomly assigned to ketamine (n=93) or placebo (n=92) subcutaneously for 3 to 5 days.
The researchers observed no significant difference between the proportion of positive outcomes between the two study arms (0.04; 95% CI, −0.1 to 0.18). The response rate was 31% for ketamine and 27% for placebo.
Pain type — nociceptive vs. neuropathic — did not predict response.
After 1 day of treatment, adverse events nearly doubled from baseline in the ketamine group (incidence rate ratio=1.95; 95% CI, 1.46-2.61). This trend continued throughout the study.
The OR for a severe-grade adverse event per day was increased in the ketamine group (OR=1.09; 95% CI, 1.00-1.18).
Twenty-five patients needed to be treated with ketamine for one additional patient to have a positive outcome (95% CI, 6-infinity), according to researchers.
“The number needed to harm, because of toxicity-related withdrawal, was six (95% CI, 4-13),” the researchers wrote.
They concluded that there is no clinical benefit of ketamine when used as an adjunct to opioids and standard coanalgesics.