Ketamine Efficacious for Treatment-Resistant Depression

FRIDAY, July 21, 2023 (HealthDay News) -- A four-week treatment course of racemic ketamine is efficacious and safe for treatment-resistant depression (TRD), according to a study published online July 14 in the British Journal of Psychiatry.

Colleen Loo, M.B.B.S., M.D., from the University of New South Wales in Randwick, Australia, and colleagues examined the acute efficacy and safety of a four-week course of subcutaneous racemic ketamine in patients with TRD in a double-blind, randomized, multicenter trial. Participants received twice-weekly subcutaneous racemic ketamine or midazolam for four weeks. Fixed-dose ketamine 0.5 mg/kg versus midazolam 0.025 mg/kg was tested initially (cohort 1; 68 patients); after a Data Safety Monitoring Board recommendation, dosing was revised to flexible-dose ketamine 0.5 to 0.9 mg/kg or midazolam 0.025 to 0.045 mg/kg, with response-guided dosing increments (cohort 2; 106 patients).

The researchers found that ketamine was more efficacious than midazolam in cohort 2 (remission rate, 19.6 versus 2.0 percent; odds ratio, 12.1; 95 percent confidence interval, 2.1 to 69.2; P = 0.005), but not in cohort 1 (remission rate, 6.3 versus 8.8 percent; odds ratio, 1.3; 95 percent confidence interval, 0.2 to 8.2; P = 0.76). Ketamine was tolerated well. Acute adverse effects resolved within two hours.

"Racemic ketamine, given by subcutaneous injection at adequate doses, is safe and efficacious in the therapy of treatment-resistant depression over a four-week treatment course," the authors write. "Benefits attenuate after treatment cessation for most patients, supporting prior evidence that ketamine should be considered as a longer-term treatment."

Several authors disclosed ties to biopharmaceutical companies; one author is named on a patent for a controlled release ketamine tablet developed by Douglas Pharmaceuticals.

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