12 Ketamine Contraindications: Who Should Not Take It

Ketamine therapy has shown remarkable results for treatment-resistant depression, anxiety, PTSD, and chronic pain. But responsible medicine means being equally clear about when a treatment should not be used. At Discreet Ketamine, Dr. Ben Soffer screens every patient carefully because safety is not negotiable.

Here is a straightforward guide to the medical and psychiatric conditions that may make ketamine therapy inappropriate -- or that require additional evaluation before proceeding.

Absolute Contraindications

These conditions generally rule out ketamine therapy entirely:

Ketamine Allergy

This is rare but it is an absolute stop. If you have had an allergic reaction to ketamine in any setting -- surgical, dental, recreational, or therapeutic -- you cannot safely receive it again.

Active Psychosis or Schizophrenia Spectrum Disorders

Ketamine can temporarily alter perception, cognition, and sense of reality. In patients with a history of psychosis, schizophrenia, or schizoaffective disorder, these effects can trigger or worsen psychotic episodes. This is one of the clearest contraindications in the clinical literature, and we do not make exceptions.

Uncontrolled Hypertension

Ketamine reliably raises blood pressure and heart rate. For patients whose blood pressure is already elevated and uncontrolled, this additional cardiovascular stress poses genuine risk -- including the risk of hypertensive crisis, stroke, or cardiac events.

If you have high blood pressure that is well-managed with medication, ketamine may still be an option. We evaluate this on a case-by-case basis with careful monitoring. Read more in our detailed article on ketamine and hypertension.

Conditions Requiring Careful Evaluation

These conditions do not automatically disqualify you, but they require additional screening, coordination with your other providers, or modified treatment protocols:

Bipolar Disorder Without Mood Stabilization

Ketamine can trigger manic or hypomanic episodes in patients with bipolar disorder, particularly if they are not currently taking a mood stabilizer. If you have bipolar I or II and are stable on a mood stabilizer such as lithium, valproate, or lamotrigine, ketamine therapy may be appropriate with close monitoring. Without mood stabilization, the risk of precipitating mania is too high.

Cardiovascular Disease

Beyond hypertension, other cardiovascular conditions -- including coronary artery disease, heart failure, arrhythmias, and history of stroke -- warrant thorough evaluation. Ketamine's sympathomimetic effects (increased heart rate, blood pressure, and cardiac output) require us to weigh the mental health benefits against cardiovascular risk. See our full discussion of ketamine and cardiovascular disease.

Moderate to Severe Liver Disease

Ketamine is metabolized primarily by the liver. In patients with significant hepatic impairment, the drug may be cleared more slowly, leading to prolonged or intensified effects. We review liver function labs before approving treatment for patients with known liver conditions.

Active Substance Use Disorder

This is nuanced. Ketamine itself is a Schedule III controlled substance with abuse potential. In patients with active, uncontrolled substance use disorders -- particularly those involving dissociatives, opioids, or alcohol -- introducing another psychoactive substance requires extreme caution. Patients who are in stable recovery may be candidates, but we assess each situation individually and often coordinate with addiction specialists.

Pulmonary Conditions

Severe respiratory conditions, particularly those that compromise airway protection or baseline oxygen levels, require evaluation. While respiratory depression from sublingual ketamine at therapeutic doses is extremely rare, patients with conditions like severe COPD or obstructive sleep apnea warrant additional consideration. See our article on ketamine and pulmonary conditions.

Situational Contraindications

These are not medical conditions per se, but circumstances that make safe treatment impossible:

No Peer Supervisor Available

At Discreet Ketamine, we require every patient to have a peer supervisor -- a trusted adult who is present in the home during the active session. This person does not need medical training; they need to be sober, present, and able to contact emergency services if necessary. If you cannot arrange a peer supervisor, at-home treatment is not safe.

Pregnancy or Breastfeeding

There is insufficient safety data on ketamine use during pregnancy and lactation. We avoid prescribing ketamine to pregnant or breastfeeding patients unless there is a compelling clinical justification and no safer alternative -- a decision that would require consultation with the patient's obstetrician.

No Access to Psychological Support

Ketamine therapy works best as part of a broader treatment plan that includes some form of psychological support -- whether that is formal psychotherapy, structured integration sessions, or at minimum a therapeutic relationship with a provider who can help you process what emerges. Patients who are seeking ketamine purely as a standalone medication without any psychological support may not be well-served by this approach. Learn more about the integration process.

Seeking Recreational Effects

We evaluate patients for medical indications. If someone's primary motivation is to experience the dissociative or psychedelic effects of ketamine rather than to treat a diagnosed mental health condition, they are not an appropriate candidate for treatment. This is not a judgment -- it is a matter of medical ethics and legal compliance.

Significant Medication Conflicts

Certain medications require evaluation before ketamine can be safely added. MAOIs, some antihypertensives, and drugs that significantly affect the CYP3A4 enzyme pathway may interact with ketamine in clinically meaningful ways. We review every patient's medication list in detail. For more, see our article on medication safety with ketamine.

The Screening Process at Discreet Ketamine

Every patient who applies for treatment at Discreet Ketamine completes a comprehensive medical intake. Dr. Soffer, a board-certified internist, personally reviews each case to determine whether at-home ketamine therapy is safe and appropriate. When we identify a contraindication, we explain why and, where possible, suggest alternative approaches or steps that might make treatment possible in the future -- such as stabilizing blood pressure or establishing a mood stabilizer regimen.

Our at-home ketamine therapy is available in Florida and New Jersey, starting at $250/month. If you want to find out whether ketamine therapy is appropriate for your specific situation, check your eligibility.

Frequently Asked Questions

Who should not take ketamine?

The clearest absolute contraindications are: a known ketamine allergy, active psychosis or schizophrenia spectrum disorders, and uncontrolled hypertension. Beyond those, several conditions require careful evaluation rather than automatic exclusion: bipolar disorder without a mood stabilizer, significant cardiovascular disease, moderate-to-severe liver disease, active substance use disorder, severe respiratory conditions, pregnancy, and breastfeeding. Every responsible at-home program screens for these before approving treatment.

Can I take ketamine if I have high blood pressure?

It depends on whether your hypertension is controlled. If your blood pressure is well-managed on medication, ketamine may still be an option with careful monitoring. Uncontrolled hypertension is an absolute contraindication because ketamine reliably raises blood pressure and heart rate, and stacking that on top of already-elevated baseline numbers risks hypertensive crisis, stroke, or cardiac events.

Can you take ketamine with bipolar disorder?

Sometimes, but only if you're stable on a mood stabilizer like lithium, valproate, or lamotrigine. Without mood stabilization, ketamine can trigger manic or hypomanic episodes — that risk is too high to proceed. With proper mood stabilization, ketamine therapy can be appropriate for the depressive phase of bipolar I or II, with close monitoring throughout treatment.

Is ketamine therapy safe during pregnancy?

We avoid prescribing ketamine to pregnant or breastfeeding patients unless there is a compelling clinical justification and no safer alternative — and that decision requires consultation with the patient's obstetrician. There is insufficient safety data on ketamine use during pregnancy and lactation to support routine prescribing in those contexts.

Can you do ketamine therapy if you have anxiety?

Yes — anxiety is one of the most common indications for ketamine therapy, including generalized anxiety disorder, social anxiety, panic disorder, and PTSD. The contraindications relate to specific medical conditions (psychosis, uncontrolled hypertension, severe cardiovascular disease, etc.), not to anxiety itself. Most patients seeking ketamine for anxiety are good candidates after standard medical screening.

Does ketamine therapy work for everyone?

No, and any provider claiming otherwise is misrepresenting it. Roughly 50-70% of patients with treatment-resistant depression respond meaningfully to ketamine. Response rates for anxiety, PTSD, and chronic pain are similar but variable. Some patients benefit dramatically; others get little or no effect. A thorough medical and psychiatric intake helps identify likely responders, but no provider can guarantee response in any individual.

What automatically disqualifies you from ketamine therapy?

The hard disqualifiers are: a known ketamine allergy, active psychosis or schizophrenia, uncontrolled hypertension, active uncontrolled substance use disorder (particularly with dissociatives, opioids, or alcohol), pregnancy or breastfeeding without a compelling clinical reason, and inability to arrange a peer supervisor for at-home sessions. Conditions like bipolar disorder, cardiovascular disease, liver disease, and certain medications require evaluation but don't automatically disqualify you.

Can you take ketamine with depression medications like Lexapro or Zoloft?

Yes, generally. SSRIs and SNRIs are considered safe to combine with ketamine. They work through different mechanisms (serotonin pathways vs. ketamine's glutamate/NMDA mechanism), and most patients continue their existing antidepressants throughout ketamine treatment. Tricyclic antidepressants and MAOIs require more careful evaluation. See our medication safety guide for the full list.

Disclaimer: Compounded ketamine for anxiety, depression, PTSD, and chronic pain is not FDA approved.