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Fatal Methaemoglobin Intoxication Following Ketamine Infusion in a Depressed MELAS Patient: A Possible Association?

J. Finsterer

Case Reports in Critical Care 2025 DOI: 10.1155/crcc/5200754 (opens in new tab)

Study at a glance

AI-extracted from the abstract
Characteristics Case report Peer reviewed
Sample size 1
Population A 32-year-old woman with MELAS syndrome due to the mtDNA variant m.3243A>G
Intervention Ketamine
Dose single infusion
Topics Esketamine Ketamine
Key findings A single ketamine infusion was followed by sudden death with 71% methemoglobinemia in a MELAS patient, suggesting a possible mitochondrial toxic effect of ketamine.

Abstract

Methemoglobinemia is defined as an increase in methemoglobin of > 2% of hemoglobin. Ketamine is increasingly used for severe depression. To our knowledge, a patient with mitochondrial encephalopathy, lactic acidosis and stroke‐like episodes (MELAS) who died suddenly and unexpectedly 1–12 h after ketamine infusion with high postmortem methemoglobin has not yet been reported. The patient was a 32‐year‐old woman with MELAS, manifesting as migraine, deafness, diabetes, bloating, and a seizure, due to the mtDNA variant m.3243A>G who received a single infusion of ketamine for the treatment of depression and posttraumatic stress disorder. Presumably, 1–12 h later, the patient died in her apartment, initially with no apparent cause for her demise. The autopsy revealed a methemoglobin level of 71% (normal: 0‐2%). Whether ketamine was responsible for the death remains speculative, but ketamine has a mitochondrial toxic effect by reducing ATP production and impairing methemoglobin reductase, which may have led to methemoglobinemia. In conclusion, ketamine should be administered with caution in MELAS patients, particularly those with a history of seizures, and if unavoidable, these patients should be carefully monitored during and after ketamine infusion.

Comparable studies

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

Study Year Design Participants
The destruction of the lower urinary tract by ketamine abuse: a new syndrome? Young recreational abusers of street-ketamine in Hong Kong referred to urology units 2008 Retrospective case series n = 59
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
Treatment of compulsive behaviour in eating disorders with intermittent ketamine infusions Chronic and treatment-resistant eating disorder patients 1998 Case series n = 15
Oral Administration of the NMDA Receptor Antagonist S-Ketamine as Add-On Therapy of Depression: A Case Series Four depressed patients taking standard antidepressants 2009 Case series n = 4
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

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