Dear Sir,
The article “Case series of Intravenous Ketamine infusion in patients with suicidal thought”[1] was an interesting and probing read which made me consider the current usage of ketamine in patients with depression. The case series is about patients with suicidal thoughts, but we would like to discuss its role in treatment-resistant depression (TRD). There are some areas of difficulty regarding ketamine use like different criteria used for treatment resistance definition, the requirement of repeated treatment for a sustained effect, abuse potential, and risks if ketamine is used without supervision. There are still several unanswered questions regarding ketamine’s effectiveness in treating TRD, including when it starts to work and how long it lasts. When classifying patients with TRD, there are notable differences due to the difficulty in reaching a consensus definition of the objective criteria for resistance (treatment length, anti-depressant dosages that are suggested, the number of treatment sequences, and the makeup of the treatment). This may also have an impact on study outcomes that measure the effectiveness of ketamine.[2]
A systematic review and meta-analysis of 28 studies concluded that a single ketamine infusion in the dose of 0.5mg/kg reduced depression scores in TRD. The initial effect was seen as early as 4 hours after the infusion, and it reached a peak at 24 hours, demonstrating the quick effects of ketamine on mood.[2] Seven days after infusion, ketamine’s effect was less pronounced, indicating that its efficacy was just temporary.[2] For the sickest patients, ketamine is thought to play a similar therapeutic effect to electro-convulsive treatment (ECT) in that it significantly reduces depressive symptoms.[3] With encouraging outcomes, several writers have looked into how well it works for quickly managing significant depressive episodes (within 24 hours).[4] Just like with ECT, the main problem with ketamine is maintaining the effects, which seemed to endure for roughly a week following a single infusion.[2] The systematic review also evaluated the long-term advantages of ketamine after receiving several infusions. Receiving multiple infusions of 0.5 mg/kg of ketamine three times a week for 2 weeks not only increased the drug’s effectiveness over a single infusion but also postponed clinical relapse.[2] Like other anti-depressants, patients on ketamine will need to receive repeated treatment over an extended length of time due to the drug’s short-lived effectiveness. The danger of abuse is increased by long-term ketamine administration due to its addictive properties, the target population’s susceptibility, and other factors.[5] Additionally, any off-label ketamine administration should take place in a strictly regulated setting and require a history of substance misuse assessment.[6]
Ketamine is a relatively new beneficial modality. Further research is required to assess the long-term usage of ketamine, the response in major depressive disorder and bipolar depression cases, and measures to assure treatment safety.[7]
Conflicts of interest
There are no conflicts of interest.
Funding Statement
Nil.
REFERENCES
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