Comparison

Racemic ketamine vs esketamine (Spravato)

Esketamine is the S-enantiomer of ketamine, delivered intranasally and FDA-approved for treatment-resistant depression. Racemic ketamine is the mixture used off-label in most clinics.

Medically reviewed by: Pending medical review(draft)Last updated: June 4, 2026Evidence: Educational synthesis - not medical advice

Racemic ketamine

Esketamine (Spravato)

Mechanism

Mixture of R- and S-ketamine; broader receptor activity beyond NMDA antagonism.

Purified S-enantiomer; higher affinity for the NMDA receptor.

Evidence

Extensive off-label clinical use and a growing body of trials.

FDA-approved based on pivotal trials in TRD; required REMS monitoring.

Onset

Hours to days.

Duration

Variable, depends on protocol and integration.

Maintenance dosing structured per FDA label.

Side effects

Dissociation, BP changes, nausea; comparable acute side-effect profile.

Dissociation, sedation, BP changes; requires in-clinic monitoring for 2 hours.

Access

Off-label at specialty clinics; lower cost; varied protocols.

FDA-approved, often insurance-covered with prior authorization; certified centers only.

Best for

Patients seeking flexible protocols or who do not qualify for esketamine.

Patients meeting TRD criteria with insurance coverage and access to a certified center.

Limits

Off-label status, variable quality control, out-of-pocket cost.

Strict monitoring, scheduling burden, insurance hurdles.

Educational use only. The content on this page is provided for general educational purposes and does not constitute medical advice, diagnosis, or treatment. Ketamine and related therapies carry risks and are appropriate only under qualified medical supervision. Always consult a licensed healthcare professional about your individual situation. Information may change as research evolves.