Ketamine for Treatment-Resistant Depression in Older Adults

Results from the world’s first trial showing the potential impact of ketamine for treatment-resistant depression provided preliminary evidence on the drug’s safety and efficacy in geriatric patients.

Researchers Colleen K Loo, MD, (University of New South Wales, Sydney, Australia) and colleagues conducted the world’s first randomized control trial assessing the efficacy and safety of ketamine to treat depression in older adults and report promising preliminary findings. An open-label phase was then conducted (J Am J Geriatr Psychiatry. 2017; doi:10.1016/j.jagp.2017.06.007).

In the trial, Dr Loo and her team analyzed the effects of different doses of ketamine in 16 adults over age 60 who had treatment-resistant depression. Researchers administered increasing doses of ketamine—through a simple subcutaneous injection—over a period of 5 weeks. Doses were individualized for each participant using a new dose-titration approach developed by the research team and collaborators.
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In addition, following the trial, participants who relapsed after remission or did not remit in the trial were then given 12 ketamine treatments in an open-label phase, so that researchers could study the effectiveness of multiple ketamine doses. An active control treatment using a drug with effects similar to ketamine was used to substitute for one of the treatment sessions. Researchers said, “Mood, hemodynamic, and psychotomimetic outcomes were assessed by blinded raters. Remitters in each phase were followed for 6 months.”

At 6-month follow up, 7 of the 14 trial-phase completers remitted with ketamine treatment, with 5 remitting at amounts below the commonly-used dose of 0.5 mg/kg. Repeated treatments were found to result in higher potential for remission or longer time to relapse. Researchers reported an overall response and remission rate of 68.8% for patients receiving ketamine treatment.

Dr Loo said, “Not only was ketamine well-tolerated by participants, with none experiencing severe or problematic side effects, but giving the treatment by a simple subcutaneous injection was also shown to be an acceptable method for administering the drug in a safe and effective way” (Eurekalert. July 22, 2017).

“Our results indicate a dose-titration method may be particularly useful for older patients, as the best dose was selected for each individual person to maximize ketamine's benefits while minimizing its adverse side effects.”—Amanda Del Signore