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Last reviewed: 7 Mar 2025
Last updated: 19 Mar 2025
19 Mar 2025

Esketamine approved in the US as the first ever monotherapy for treatment-resistant depression in adults

For the first time, the Food and Drug Administration (FDA) has approved a ketamine-related drug as a standalone treatment for adults with major depressive disorder (MDD). Esketamine nasal spray is approved for patients who have treatment-resistant depression (TRD) - defined as an inadequate response to at least two oral antidepressants.

The approval follows a multicentre randomised controlled trial which demonstrated the rapid efficacy of esketamine monotherapy. Within the first 24 hours of the initial dose, participants experienced significant improvements in their Montgomery-Asberg Depression Rating Scale (MADRS) total score, with the effects persisting for at least 4 weeks. By the fourth week, 22.5% of patients receiving esketamine had achieved remission (MADRS total score ≤12), compared to 7.6% in the placebo group.

Until now, esketamine had been approved in the US exclusively as an adjunctive therapy alongside an oral antidepressant for two indications in adults: as a treatment for TRD, and for those with MDD experiencing suicidal ideation or behaviour.

This expanded indication makes esketamine accessible to individuals with TRD who are not on an antidepressant or who wish to discontinue their current one, which may help to overcome treatment barriers owing to negative experiences with oral antidepressants, such as poor tolerability.

Despite growing clinical adoption of esketamine, several questions remain. The optimal patient profile for treatment response, how long therapeutical effects might persist, and the appropriate duration of therapy all require further investigation. While no longer considered a last-resort treatment, esketamine is not a first- or second-line treatment.

Esketamine is approved only for use in an appropriate certified clinical setting under the supervision of a health care provider; typically this will mean referring to a designated treatment facility offering esketamine. A key practical consideration is the logistical and occupational commitments required of patients; for example, the need to take time away from work and to arrange necessary transport and support. The drug must be self-administered by the patient, who is supervised by a health care provider in a certified medical office, and the patient monitored for at least 2 hours because of the risk of sedation, respiratory depression, difficulty with attention, judgement and thinking (dissociation), suicidal thoughts and behaviours, and the potential for drug misuse. For these reasons, esketamine is only available via a restricted distribution programme in the US.

People with poorly controlled hypertension or pre-existing aneurysmal vascular disorders may be at increased risk for adverse cardiovascular or cerebrovascular effects. Esketamine is contraindicated in patients with aneurysmal vascular disease, arteriovenous malformation, or intracerebral haemorrhage.

Esketamine is available in Europe; however, it is not currently approved for monotherapy. Availability of esketamine varies according to the country of practice and relevant regulatory approval.

See Management: approach

See Management: treatment algorithm

Original source of update

Summary

Definition

History and exam

Key diagnostic factors

  • presence of risk factors
  • depressed mood
  • anhedonia
  • functional impairment

Other diagnostic factors

  • weight change
  • libido changes
  • sleep disturbance
  • changes in movement
  • low energy
  • excessive guilt
  • poor concentration
  • suicidal ideation
  • somatic symptoms
  • bipolar disorder excluded
  • substance abuse/medication side effects excluded
  • medical illness excluded
  • schizophrenia excluded

Risk factors

  • postnatal status
  • personal or family history of depressive disorder or suicide
  • history of an anxiety disorder, or anxiety symptoms
  • adverse childhood experiences
  • dementia
  • corticosteroid use
  • interferon use
  • oral contraceptive use
  • co-existing medical conditions
  • female sex
  • comorbid substance use
  • personality disorders
  • history of violent victimisation
  • obesity
  • older age (≥65 years)
  • separated/divorced marital status

Diagnostic investigations

1st investigations to order

  • clinical diagnosis
  • metabolic panel
  • FBC
  • thyroid function tests
  • Patient Health Questionnaire-2 (PHQ-2)
  • Patient Health Questionnaire-9 (PHQ-9)
  • Edinburgh Postnatal Depression Scale
  • Geriatric Depression Scale
  • Cornell Scale for Depression in Dementia

Investigations to consider

  • 24-hour free cortisol
  • vitamin B12
  • folic acid

Treatment algorithm

Contributors

Authors

Dean F. MacKinnon, MD

Associate Professor

Psychiatry and Behavioral Sciences

The Johns Hopkins Hospital

Baltimore

MD

Disclosures

DFM declares that he has no competing interests.

Acknowledgements

Dr Dean F. MacKinnon would like to gratefully acknowledge Dr Roger S. McIntyre, Dr Tonya Fancher, and Dr Richard Kravitz, the previous contributors to this topic.

Disclosures

RSM has received research funds from Stanley Medical Research Institute and National Alliance for Research on Schizophrenia and Depression (NARSAD). RSM is on the advisory board for AstraZeneca, Bristol-Myers Squibb, France Foundation, GlaxoSmithKline, Janssen-Ortho, Solvay/Wyeth, Eli Lilly, Organon, Lundbeck, Biovail, Pfizer, Shire, and Schering-Plough. RSM is on the Speakers Bureau for Janssen-Ortho, AstraZeneca, Eli Lilly, Lundbeck, Biovail, and Wyeth. RSM has received research grants from Eli Lilly, Janssen-Ortho, Shire, and AstraZeneca. RSM has received travel funds from Bristol-Myers Squibb. TF declares that she has no competing interests. RK has received research grants from Pfizer on non-depression-related topics.

Peer reviewers

Christopher Dowrick, BA MBChB MSc MD

Emeritus Professor

University of Liverpool

UK

Disclosures

CD has been reimbursed by Novartis for participating in an educational event.

Erin K. Ferenchick, MD

Center for Family and Community Medicine

Columbia University Medical Center

Upper Manhattan

NY

Disclosures

EKF declares that she has no competing interests.

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