Accidental Ketamine Overdose on Induction of General Anesthesia

The diverse effects of ketamine, jack-of-all-trades: a narrative review

Ketamine, an N-methyl-D-aspartic acid receptor antagonist that was first discovered in 1962, has become established in anaesthesia providing dose-dependent anaesthetic, sedative, and analgesic effects. Ketamine, however, also acts on a wide range of other cellular targets, resulting in interesting and diverse effects on both physiological and pathological processes. Potential beneficial properties of ketamine include cardiovascular stability for patients undergoing sedation or anaesthesia, analgesia in both acute and chronic pain, bronchodilation in severe refractory asthma, anti-inflammatory properties particularly in sepsis, tumour inhibition, and antidepressant properties with marked ability to reverse suicidal ideation. The reluctance to adopt ketamine into routine practice is likely attributable in part to the stigma and negative reputation associated with its perceived side-effects and potential for abuse. This review explores the diverse properties and therapeutic potentials of ketamine being investigated across different fields whilst also identifying areas for ongoing and future research. Given the diverse range of potential benefits and promising early work, ketamine should be the focus of ongoing research in multiple different specialty areas. This includes areas relevant to anaesthesia and perioperative medicine, such as acute and chronic pain management, ICU sedation, and even tumour suppression in those undergoing surgical resection of malignancies.

Treatment and outcome following substantial ketamine overdose in a dog

A 9-year-old, 3.7 kg (8.14 lb) neutered male Yorkshire terrier mix was treated following a ketamine overdose after subcutaneous ureteral bypass surgery. Due to an error in communication and misinterpretation of an electronic treatment sheet, the dog was inadvertently placed on a continuous rate infusion (CRI) of ketamine at 67.6 mg/kg per hour, rather than the intended 0.2 mg/kg per hour rate. Four hours after initiation of the ketamine CRI, the dog developed signs indicative of a ketamine overdose including tachycardia, hyperthermia, anisocoria, and hypoglycemia. It was determined the dog had received an iatrogenic overdose of ketamine; the infusion had been running at 67.6 mg/kg per hour, resulting in 270 mg/kg of ketamine over 4 h. Aggressive supportive measures were undertaken, and the dog gradually recovered over an 18-hour period, without lasting consequences of the overdose. To the authors' knowledge, there are no current published reports of a ketamine overdose of this magnitude in a dog. This case report documents an iatrogenic 338 times intravenous ketamine overdose in a dog, which was successfully managed with supportive care. In addition, it highlights the importance of doctor-technician communication and the potential errors in using electronic treatment sheets.

Overdoses and deaths related to the use of ketamine and its analogues: a systematic review

Background: Although the misuse of ketamine constitutes a worldwide issue, ketamine is quickly taking its place as a therapeutic option in the management of several mental disorders. However, the use of ketamine and/or its analogues, as well as combinations with other drugs, can be fatal.Objective: To outline the cases of overdoses and deaths related to the use of ketamine and/or its analogues, as reported in the scientific literature. To investigate if ketamine is safe in a therapeutic context, particularly in its use as an antidepressant.Methods: Electronic searches were performed on three medical databases. Articles describing cases of overdose and/or death associated with ketamine and/or its analogues were included. After the removal of duplicates, title analysis and full-text analysis, 34 articles were included in this review.Results: Eighteen articles described fatal cases and sixteen described overdoses. Poly-substance use was mentioned in 53% of the selected articles. Most cases were males and the ages varied from two to 65 years old. A total of 312 overdose cases and 138 deaths were reported. In both death reports and overdose cases, ketamine was preponderant: 89.1% and 79%, respectively. No cases of overdose or death related to the use of ketamine as an antidepressant in a therapeutic setting were found; most of the deaths occurred in the circumstances of polydrug use and overdoses left no sequelae.Conclusion: There is legitimate concern about the risks involving the use of ketamine and its analogues, especially in recreational settings. On the other hand, ketamine as medicine is considered safe and it is listed as an essential medicine by the World Health Organization. Although clinicians must remain vigilant, this should not deter appropriate prescription.