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Case series: Clinical response of ketamine infusion in patients with treatment-resistant depression

Pallavi Preetinanda, Srikrishna Nukala, Abhilash Garapati, Srinivas Singisetti, Niveditha Vasireddy, Vidya Sanapala, Ramya Spandana Tata

Telangana Journal of Psychiatry 2024 DOI: 10.4103/tjp.tjp_16_24 (opens in new tab)

Study at a glance

AI-extracted from the abstract
Characteristics Case series Open-label Case report Peer reviewed
Sample size 5
Population Adults with treatment-resistant depression, defined as persistent significant depressive symptoms despite two different antidepressant regimens each used for more than 6 weeks
Intervention Ketamine
Dose 0.5 mg/kg body weight
Duration Six infusions over 2 weeks, thrice weekly on alternate days; MADRS repeated 2 weeks post-infusion
Measures Montgomery–Åsberg Depression Rating Scale (MADRS)
Topics Depression Esketamine Ketamine
Key findings Five patients with treatment-resistant depression received six open-label intravenous ketamine infusions at 0.5 mg/kg over two weeks and were reported to show clinical improvement, with response defined as a more than 50% decrease in MADRS scores. The authors argue that this low-rate, serial dosing schedule supports ketamine's efficacy in treatment-resistant depression.

Abstract

Treatment-resistant depression (TRD) is one of the most debilitating conditions that does not respond to conventional pharmacotherapy. Ketamine is a recently used effective treatment option in depressive disorders with a novel mechanism of action. Still, studies estimating the improvement of depressive symptoms in TRD with multiple doses of ketamine are limited. Hence, we report 5 TRD cases that received six open-label intravenous (IV) infusions of ketamine. Five cases of TRD, diagnosed by a clinician defined as the persistence of significant depressive symptoms despite being treated with two different antidepressant regimens, each used for more than 6 weeks were evaluated to identify the need for ketamine infusion and were administered six open-label IV infusions of ketamine which were done at the rate of 0.5 mg/kg body weight, thrice weekly, on alternative days for 2 weeks, following standard protocol. The Montgomery–Åsberg Depression Rating Scale (MADRS) scores were administered by the clinician before the infusion and were repeated after 2 weeks post-infusion. The response was recorded and was seen as a more than 50% decrease in MADRS scores and our cases showed significant improvement clinically. Our low infusion rate and serial dosing trial with ketamine support the efficacy of this drug in TRD. Approximately 30% of patients with major depressive disorder are treatment-resistant. New treatment strategies are needed to address that portion of cases. Subanesthetic doses of IV ketamine have a rapid antidepressant effect in TRD, this signifies the potential of ketamine to be used in this regard.

Comparable studies

Other case reports and case series on ketamine for depression, most cited first.

Study Year Design Participants
Electroconvulsive Therapy, Ketamine, and Esketamine in a Patient with Major Depressive Disorder and Multiple Comorbidities: A Case Report over 10-year Treatment from Adolescence to Adulthood. A patient with treatment-resistant depression and comorbid generalized anxiety... 2025 Case report n = 1
A longitudinal case series of IM ketamine for patients with severe and enduring eating disorders and comorbid treatment‐resistant depression Patients with enduring eating disorders and treatment-resistant depression 2021 Case series n = 4
Effects of intranasal (S)-ketamine on Veterans with co-morbid treatment-resistant depression and PTSD: A retrospective case series Veterans with co-morbid depression and PTSD 2022 Retrospective case series n = 35
Case report: Intramuscular ketamine or intranasal esketamine as a treatment in four patients with major depressive disorder and comorbid anorexia nervosa Patients with anorexia nervosa and a comorbid depressive disorder treated at a private... 2023 Case report n = 4
Repeated oral esketamine in patients with treatment resistant depression and comorbid posttraumatic stress disorder Patients with treatment-resistant depression and comorbid PTSD 2023 Case series n = 5

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