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How to Give Oral Ketamine Therapy for Treatment of Resistant Depression and Suicidality: A Critical Review

Mohan Dabas, Swarndeep Singh, Pankaj Verma

Clinical Psychopharmacology and Neuroscience November 4, 2026 DOI: 10.9758/cpn.26.1453 (opens in new tab)

Study at a glance

AI-extracted from the abstract
Characteristics Systematic review Randomized Peer reviewed
Population People with depression or suicidality receiving oral ketamine, across 16 reviewed studies
Intervention Oral ketamine
Topics Depression Esketamine Ketamine
Key findings Across 16 studies, oral ketamine was generally associated with clinically meaningful improvements in depressive symptoms and suicidality and showed better tolerability than intravenous ketamine. Dosing was highly heterogeneous (11 fixed-dose, 5 individualized titration protocols). The authors contend that preliminary evidence suggests repeated sessions and dose titration may improve tolerability and outcomes, but that equivalence with intravenous ketamine is not established and randomized trials are needed.

Abstract

Objective: To critically review the empirical literature on oral ketamine dosing strategies and administration procedures; and provide pragmatic clinical considerations for its use in out-patient psychiatric settings for treatment-resistant depression and suicidality.Methods: A structured search of PubMed and Google Scholar was conducted to identify peer-reviewed studies published till April 2026.Studies including at least ten participants with depression or suicidality receiving oral ketamine were narratively synthesized.Results: Sixteen studies were reviewed.Dosing strategies showed substantial heterogeneity.They were broadly divided into fixed-dosing (n = 11); and individualized dose-titration (n = 5) protocols.Considerable heterogeneity was observed in patient populations, dosing regimens, treatment duration, and outcome measures.Oral ketamine was most commonly prepared by diluting injectable racemic ketamine in water or juice.Several studies employed gradual ingestion ("sipping"), although direct pharmacokinetic comparisons with bolus administration are lacking.Across study designs, oral ketamine was generally associated with clinically meaningful improvements in depressive symptoms and suicidality and demonstrated superior tolerability profile compared to intravenous ketamine.Preliminary evidence suggests that repeated treatment sessions and individualized dose-titration strategies may improve tolerability and clinical outcomes; however, these observations require confirmation in adequately powered comparative trials.Conclusion: Oral ketamine therapy appears to be a promising and safer alternative to intravenous ketamine infusion for providing rapid relief in resistant depression and suicidality.Although preliminary findings suggest efficacy comparable to other ketamine administration routes, equivalence with intravenous ketamine has not been unequivocally established.Standardized treatment protocols and high-quality randomized trials are needed before definitive clinical recommendations can be made.

Comparable studies

Other systematic reviews and meta-analyses on ketamine for depression, most cited first.

Study Year Design Participants
Ketamine and Other NMDA Antagonists: Early Clinical Trials and Possible Mechanisms in Depression Participants with major depression in placebo-controlled, double-blind, randomized... 2015 Systematic review and meta-analysis
Side-effects associated with ketamine use in depression: a systematic review. Patients with depression 2018 Systematic review
Comparative efficacy of racemic ketamine and esketamine for depression: a systematic review and meta-analysis Adults with unipolar or bipolar major depression 2020 Systematic review and meta-analysis n = 1,877
Single-dose infusion ketamine and non-ketamine N-methyl-D-aspartate receptor antagonists for unipolar and bipolar depression: a meta-analysis of efficacy, safety and time trajectories Patients with major depressive disorder or bipolar depression 2016 Systematic review and meta-analysis n = 588
The use of ketamine as an antidepressant: a systematic review and meta‐analysis People with major depressive disorder or bipolar disorder receiving ketamine infusion 2015 Meta-analysis n = 437

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