Evidence memo / Neuro & mental health

Ketamine / esketamine

Also: esketamine · Spravato · racemic ketamine

Ketamine and its component esketamine are dissociative anesthetic drugs now used for severe depression. Esketamine (Spravato) is an FDA-approved nasal spray for treatment-resistant depression and for depression with suicidal thoughts, given under medical supervision, while racemic ketamine is widely used off-label with substantial trial support. The Watchlist boundary is keeping these to their approved and evidence-based depression uses and noting the abuse, dissociation, and monitoring requirements that come with them.

Approved for specific usesPost-market evidenceSafety / regulatory watch

The verdict

Our read at a glance.

Whether ketamine and esketamine's approved and trial-supported use in severe depression supports the broader mood, wellness, and at-home claims attached to them.

The signal
Esketamine is FDA-approved for treatment-resistant depression and for depression with suicidal thoughts, based on randomized trials, and racemic ketamine has substantial trial evidence for rapid, short-lived antidepressant effects. Benefits can fade without continued treatment, and the drugs require supervision.
The unknown
How to maintain benefit safely over time, the risks of long-term and less-supervised use, and how to separate evidence-based use from loosely regulated clinic and at-home models.
Our read
A genuine, fast-acting advance for severe depression, used under supervision, not a casual wellness treatment. Esketamine is approved and ketamine is well studied for depression, but the dissociation, abuse, and monitoring requirements mean the safe use is the supervised, specific-indication one.

The mechanism

How it works.

Ketamine is a dissociative anesthetic, and esketamine is its more potent S-enantiomer. Both block the NMDA glutamate receptor, and the leading explanation is that this blockade produces a rebound surge of glutamate that drives AMPA-receptor signaling and, downstream, the rapid formation of new synaptic connections. That synaptic effect is thought to explain why a single dose can lift severe depression within hours, unlike serotonin-based antidepressants that take weeks. The dissociation and sedation come from the same NMDA blockade, and dosing is supervised.

Safety & regulatory boundary

The consequential part.

Esketamine is approved only with a risk program requiring in-clinic administration and monitoring because of dissociation, sedation, blood-pressure effects, and abuse potential. Racemic ketamine for depression is largely off-label and also carries abuse and bladder and cognitive risks with heavy use. Approved supervised use does not validate unsupervised at-home or wellness use, and these are controlled drugs, not supplements.

What's next

What we're watching.

Long-term outcome and safety data, the role of at-home and off-label models, and regulatory actions on ketamine clinics.

Context

Why this is discussed.

Ketamine and esketamine are a major shift in depression treatment because they work quickly and differently from standard antidepressants, which has driven both clinical use and a wave of clinics and at-home offerings.

The evidence base

21 cited references.

Regulatory & labels1

DailyMed label: Spravato

Janssen Pharmaceuticals Inc. (FDA label) · 2026

Indexed literature (PubMed)12

Pharmacotherapy: Ketamine and Esketamine

Feeney A et al. · Psychiatr Clin North Am · 2023

Long-term safety of ketamine and esketamine in treatment of depression

Nikayin S et al. · Expert Opin Drug Saf · 2022

Keep reading

Related published memos.