When Ketamine Is Not Appropriate: Medical and Psychiatric Contraindications

Ketamine can be a powerful treatment for depression, PTSD, anxiety, trauma, and chronic pain. Particularly for individuals who have not responded to traditional medications. When used responsibly, many patients experience relief, clarity, and renewed emotional flexibility. However, ketamine is not appropriate for every situation or every patient.

Safe, ethical ketamine treatment requires recognizing when to prescribe, and just as importantly, when not to. This guide explains the medical and psychiatric scenarios where I would not prescribe ketamine, and why those boundaries exist. 1. Psychosis or History of Schizophrenia Ketamine temporarily alters perception and internal-external boundaries.

For individuals with a history of psychosis or schizophrenia, ketamine can destabilize them and cause worsening hallucinations, paranoia, or disorganized thinking. 2. Bipolar Disorder Without a Mood Stabilizer Ketamine can lift bipolar depression, but without a mood stabilizer, it may trigger: Mania Agitation Mixed states (which carry exceptionally high suicide risk)Bipolar patients must be on a mood stabilizer such as lithium, lamotrigine, or valproate. If there has been recent mania, ketamine is delayed until stable.

1. Acute Suicidality With Immediate Safety Risk Ketamine often reduces suicidal thinking, but outpatient ketamine requires that the patient can stay safe between sessions. If there is: Active intentA plan or accessible means Inability to contract for safety→ Hospital-based or intensive support is the safer first step. Once safety stabilizes, outpatient ketamine may become appropriate.

1. Uncontrolled Hypertension or Cardiovascular Instability Ketamine temporarily increases heart rate and blood pressure. Ketamine is not appropriate for patients with: Severe uncontrolled hypertension Recent heart attack or cardiac event Uncontrolled arrhythmias Blood pressure and heart must be stabilized first. 5.

Moderate to Severe Liver Dysfunction Ketamine is processed in the liver. When liver function is compromised, ketamine may accumulate unpredictably. Mild impairment → Possible with caution Moderate/severe impairment → Contraindicated6. Active Substance Use Disorder For patients actively misusing alcohol, stimulants, opioids, or dissociatives, ketamine may: Reinforce addictive patterns Intensify emotional dysregulation Increase relapse vulnerability Stabilization comes first, then ketamine can be reconsidered safely.

1. Seeking Ketamine Only for “The Experience”Ketamine is not prescribed for: Curiosity or noveltyA psychedelic “trip”Recreational or spiritual tourism Medical ketamine is a treatment with clinical goals, not a sensation-seeking experience. A clear medical indication is required. 8.

Pregnancy or Breastfeeding Out of caution and due to possible transfer to the fetus or breastmilk, ketamine is avoided during pregnancy and breastfeeding unless the situation is urgent and medically necessary. 9. Lack of a Safe Home Environment or Peer Supervisor During Treatment Ketamine temporarily alters awareness, coordination, and sensory interpretation. During the dissociated phase, patients must not be alone.

Ketamine is not prescribed when a patient does not have: A quiet, stable, and safe home environmentA peer supervisor physically present during dosing The ability to rest after treatment Emotional support between sessions

What the Peer Supervisor

DoesA peer supervisor is a calm, trusted adult who stays in the room during the ketamine experience to ensure: Safety - Prevent walking, falling, or unsafe movements during dissociation Reassurance - Offer gentle grounding if the patient is confused or anxious Monitoring - Observe for distress and contact the clinician if needed Grounding Support - Help the patient return to baseline after the experience They do not guide the experience or provide therapy — they ensure physical and emotional safety. When support is in place, ketamine sessions are safer, smoother, and more deeply therapeutic. 10. Medication Conflicts Some medications reduce ketamine’s therapeutic effect or increase cardiovascular risk.

Benzodiazepines (Xanax, Klonopin, Ativan) — Can blunt ketamine’s antidepressant effects, concurrent use can increase risk of sedation and respiratory depression High-dose stimulants — Can raise heart rate and blood pressure too high Clozapine — Sedation and blood pressure instability risk Recent MAO Is — Risk of hypertensive reaction These do not always prevent treatment, but they require careful evaluation and planning. 11. Lack of Psychological Support or Integration Resources Ketamine brings emotional material to the surface. Patients need space and support to process what arises.

If a patient has: No therapist No support network No openness to reflection We build support first, then reconsider ketamine. 12. Allergy or Hypersensitivity to Ketamine Rare, but an absolute contraindication.

Conclusion

Ketamine can be transformative, but only in the right clinical context. Safe care means recognizing when ketamine helps, and when the priority is stabilization first. When the foundation is in place, emotional support, safe environment, medication stability, readiness for integration, then ketamine becomes not only safe, but profoundly effective.

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