Peer-influenced content. Sources you trust. No registration required. This is HCN.

Psych Congress NetworkKetamine Treatment in TRD Should Last 4 Weeks or More for Antidepressant Benefit

Previous trials suggested that intravenous racemic ketamine was effective, but phase 3 trials were necessary to confirm the findings.

The use of subcutaneous racemic ketamine for treatment-resistant depression (TRD) has been thoroughly investigated in a study led by Dr. Colleen Loo. Conducted in Australia and New Zealand, the study explored the efficacy and safety of a 4-week course of this treatment method among TRD patients, comparing flexible-dose versus fixed-dose approaches and analyzing practical implications for the future.

Key Points:

  • The study assessed the acute efficacy and safety of a 4-week course of subcutaneous racemic ketamine for TRD, with a double-blind, randomized, active-controlled trial design.
  • Midazolam was chosen as the active control drug, and ketamine’s efficacy was found to be dose-related.
  • Two cohorts were compared: fixed-dose (cohort 1) and flexible response-guided dosing (cohort 2), with the latter showing significant antidepressant efficacy.
  • Cohort 1 did not yield significant results due to an insufficient dose.
  • A prototype of the Ketamine Side Effect Tool (KSET) was used to monitor safety comprehensively, with no notable concerns identified.

Additional Points:

  • The study emphasizes the importance of individualized, response-guided dosing and an adequate dose for efficacy.
  • It also highlights the necessity for ongoing treatment beyond 4 weeks to maintain antidepressant effects.
  • Long-term effects of ongoing ketamine treatment still require careful monitoring and data collection.


  • The study’s findings present subcutaneous ketamine as a practical and safe treatment option for TRD, especially when individualized dosing approaches are employed, and emphasize the need for ongoing treatment and careful monitoring.

“Our study used a very comprehensive and detailed approach to monitor safety. Many studies have reported on the safety of ketamine in the 2 hours after each treatment, but our study also examined for cumulative effects over multiple treatments—this is important because the longer-term effects (eg, on the bladder lining) are different from short-term effects in the 2 hours after dosing.”

Colleen Loo, MBBS (Hons), FRANZCP, MD (research doctorate)
Clinical Psychiatrist and Professor of Psychiatry
University of New South Wales and the Black Dog Institute
Sydney, Australia
The Healthcare Communications Network is owned and operated by IQVIA Inc.

Click below to leave this site and continue to IQVIA’s Privacy Choices form