Esketamine vs. Ketamine: Clinical and Policy Distinctions in U.S. Psychiatric Care

Esketamine and Ketamine: Regulatory Status and Clinical Use

Esketamine, marketed as Spravato by Janssen Pharmaceuticals, is the only ketamine-based therapy approved by the U.S. Food and Drug Administration (FDA) for treatment-resistant depression (TRD) and major depressive disorder (MDD) with acute suicidal ideation. In contrast, generic racemic ketamine, while widely available and used off-label for depression, has not been approved by the FDA for any psychiatric indication. This regulatory distinction shapes prescriber liability, insurance reimbursement, and clinical protocols in the United States.

Esketamine is administered as a nasal spray under a Risk Evaluation and Mitigation Strategy (REMS) program, requiring in-clinic monitoring for at least two hours post-dose. Ketamine, typically delivered intravenously or intramuscularly, is not subject to REMS but is regulated as a Schedule III controlled substance. The lack of FDA approval for psychiatric use means that ketamine clinics operate in a legal gray area, with standards of care largely determined by professional guidelines and state medical boards rather than federal oversight.

Mechanistic and Clinical Differences: Efficacy and Safety

Esketamine and ketamine share a common mechanism as N-methyl-D-aspartate (NMDA) receptor antagonists, but esketamine is the S-enantiomer of ketamine and may have different pharmacodynamic properties. Clinical trials supporting esketamine’s approval (e.g., TRANSFORM-1, TRANSFORM-2; ClinicalTrials.gov NCT02417064, NCT02418585) demonstrated statistically significant, though modest, improvements in depressive symptoms compared to placebo. Generic ketamine, in contrast, has a broader base of open-label and small randomized studies, with some evidence suggesting rapid antidepressant effects but lacking large-scale, FDA-reviewed data for psychiatric indications.

Safety profiles differ in both perception and documentation. Esketamine’s REMS program addresses risks of dissociation, sedation, and potential misuse, while ketamine’s off-label use is associated with variable monitoring protocols and less consistent adverse event reporting. Notably, esketamine’s formal approval and safety infrastructure may reduce prescriber liability compared to off-label ketamine, a factor that is increasingly relevant as malpractice insurers scrutinize psychedelic-assisted therapies.

Policy, Access, and Insurance Coverage

Insurance coverage for esketamine is generally available under most commercial and government plans due to its FDA approval, although prior authorization and step therapy requirements are common. By contrast, ketamine infusions for depression are rarely reimbursed, leaving patients to pay out-of-pocket or seek care through specialized clinics. This creates disparities in access, with esketamine primarily available in large health systems and ketamine more accessible in private practice settings, often at significant personal expense.

From a policy standpoint, the distinction between FDA-approved and off-label use is not merely academic. Prescribers must weigh the legal protections and clinical evidence supporting esketamine against the broader, but less regulated, use of ketamine. Some state medical boards have issued guidance on ketamine for depression, but there is no national consensus on standards of care. As a result, clinicians face uncertainty regarding best practices, especially in the context of evolving research and patient demand.

• Non-obvious implication: Some malpractice insurers are beginning to differentiate between esketamine and ketamine in their underwriting, with higher premiums or exclusions for off-label ketamine administration. This trend may influence clinic business models and referral patterns more than clinical trial data alone.

Risks, Unknowns, and Forward Outlook

Both esketamine and ketamine carry risks of dissociation, abuse potential, and cardiovascular effects, but the structured monitoring required for esketamine may mitigate some safety concerns. Long-term data on both agents in psychiatric populations remain limited, and questions persist about optimal dosing, maintenance strategies, and comparative effectiveness. The lack of head-to-head randomized controlled trials (RCTs) between esketamine and ketamine leaves clinicians without definitive guidance on which agent is superior for specific patient populations.

Looking ahead, ongoing research—including the NIH-funded ASCEND trial (NCT05340374) comparing intravenous ketamine to esketamine—may clarify efficacy and safety differences. Meanwhile, policy debates about insurance coverage, liability, and clinical standards are likely to intensify as more patients seek rapid-acting antidepressant options. The evolving landscape underscores the need for clear, evidence-based guidelines and transparent communication with patients about the benefits and limitations of each approach.

How we research: This article was written and reviewed by Dr. Alex M. Klein, MD, MSc, psychiatrist and clinical researcher, on 2026-10-21. Primary sources include FDA approval documents, ClinicalTrials.gov records, and recent state medical board guidance. For verification, see the FDA Spravato approval and ASCEND trial registry.