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.

When patients ask me what disqualifies someone from ketamine therapy, the honest answer is shorter than most people expect. The list of true contraindications is small, well-defined, and based on decades of anesthesia data. A few are absolute, and I will not prescribe around them no matter how much someone wants treatment. Many more are simply a screening conversation. Here is the same checklist I use on every intake.

Quick answer

Most adults with depression, anxiety, PTSD, or treatment-resistant mood symptoms qualify for at-home ketamine therapy. The absolute contraindications (the ones that mean no, not under any circumstances) are: uncontrolled high blood pressure, active psychosis or schizophrenia, active mania, recent heart attack or stroke, severe liver disease, pregnancy, and active substance use disorder involving ketamine or other dissociatives. Everything else (SSRIs, ADHD meds, mild hypertension, history of trauma, age over 65) is a screening conversation, not a disqualification. About 85-90% of adults who apply to a reputable at-home ketamine program are medically cleared after intake, based on aggregated screening data from telehealth ketamine providers.

The short version: who cannot take ketamine

If any of these describes you, at-home sublingual ketamine is not appropriate. Some of these may still allow for in-clinic IV ketamine under monitored anesthesia, but not unsupervised home dosing.

1. Uncontrolled high blood pressure (resting BP above ~160/100 mmHg or a history of hypertensive emergency)
2. Active or unstable cardiovascular disease: recent heart attack (within 6 months), unstable angina, recent stroke or TIA, severe heart failure, or known aortic aneurysm
3. Active psychosis, schizophrenia, or schizoaffective disorder
4. Active mania or untreated bipolar I disorder (bipolar II with stable mood is screened case-by-case)
5. Pregnancy or active breastfeeding
6. Severe liver disease (decompensated cirrhosis, acute hepatitis, or AST/ALT more than 3x upper limit of normal)
7. Active substance use disorder involving ketamine, PCP, or other dissociatives, plus active untreated alcohol use disorder
8. Increased intracranial pressure (recent head injury, untreated brain tumor, or known CSF abnormality)
9. Severe untreated sleep apnea (without CPAP compliance)
10. Known allergy or hypersensitivity to ketamine

If none of those apply, you are very likely a candidate. The next sections explain why each one matters and what counts as a relative versus absolute disqualifier.

Absolute contraindications: why these are non-negotiable

These conditions generally rule out at-home 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

Ketamine is a glutamate NMDA-receptor antagonist, and at higher doses it can produce dissociation and brief perceptual changes that look pharmacologically similar to a psychotic episode. In someone with no psychotic illness this resolves within an hour and is therapeutic. In someone with active psychosis or schizophrenia, ketamine can worsen and prolong symptoms. This is well-established in the American Psychiatric Association consensus on ketamine and esketamine (Sanacora et al., JAMA Psychiatry, 2017), which lists primary psychotic disorders as a contraindication for psychiatric ketamine use. This is one of the few times I will not prescribe at all. There is no monitoring setup at home that makes it safe.

Uncontrolled hypertension and unstable cardiovascular disease

Ketamine reliably raises blood pressure and heart rate for about 30-60 minutes after dosing. In a healthy adult, systolic BP typically goes up by 15-25 mmHg and heart rate by 10-20 bpm. That is a feature, not a bug (it is how the drug acts on the sympathetic nervous system), but it means someone whose cardiovascular system is already stressed cannot safely absorb the load.

The Sanacora et al. APA consensus lists uncontrolled hypertension and unstable cardiovascular disease as absolute contraindications, and that has not meaningfully changed since. The systematic side-effect review by Short et al., Lancet Psychiatry, 2018 is consistent: most adverse effects at subanesthetic doses are mild and transient, and serious events cluster in patients with pre-existing cardiovascular instability.

In practice: if your blood pressure is well-controlled on medication and your numbers run consistently below ~140/90, you can usually be cleared. If your BP is bouncing into the 160s/100s, we treat the BP first, then revisit ketamine. Read more in our detailed article on ketamine and hypertension and our full discussion of ketamine and cardiovascular disease.

Active mania or untreated bipolar I

Ketamine has rapid antidepressant effects, and for someone who is already cycling toward mania, that push can tip them into a full manic episode. The evidence base on ketamine in bipolar depression (including Diazgranados et al., Archives of General Psychiatry, 2010 and the Grunebaum et al. midazolam-controlled trial in bipolar depression with suicidal thoughts (Bipolar Disorders, 2017)) suggests ketamine can be safe and effective for stable bipolar II depression on a mood stabilizer, but actively manic patients and unmedicated bipolar I are excluded from every well-run study. We screen carefully for any mood elevation in the past 90 days and require an existing mood stabilizer such as lithium, valproate, or lamotrigine for any bipolar diagnosis.

Pregnancy and breastfeeding

Ketamine crosses the placenta and is excreted in breast milk. There are no controlled human pregnancy data establishing safety. The FDA Spravato (esketamine) prescribing information lists pregnancy as a contraindication, and the same caution applies to off-label sublingual ketamine. We do not prescribe to anyone who is pregnant, actively trying to conceive, or breastfeeding, and we ask patients to use effective contraception during treatment.

Severe liver disease

Ketamine is metabolized primarily by the liver. In patients with significant hepatic impairment (decompensated cirrhosis, acute hepatitis, or AST/ALT more than 3x the upper limit of normal), 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 involving dissociatives

Ketamine has known abuse potential. In someone with active ketamine, PCP, or other dissociative use disorder, prescribing it at home is not appropriate, both for relapse risk and because tolerance changes the dose-response in unpredictable ways. The Sanacora et al. APA consensus explicitly addresses substance-use considerations, and standard addiction medicine guidance agrees. Active alcohol use disorder is a separate issue covered in our ketamine and alcohol guide: drinking the day of dosing is dangerous, and active heavy drinking is a contraindication until stabilized.

Relative contraindications: things that need a closer look

These conditions require extra screening, sometimes a specialist letter, sometimes a lower starting dose, but most patients in these categories can still be safely treated.

For the full picture on drug interactions, see our medication safety with ketamine guide.

What is NOT a contraindication (despite what the internet says)

A surprising amount of misinformation circulates about who "can't" do ketamine. Here are the most common myths I correct on intake calls:

• "I'm on an SSRI, so I can't do ketamine." Almost always false. The vast majority of patients on SSRIs do ketamine therapy without modification. The relevant interaction concerns are tramadol, MAOIs, and high-dose lithium, not standard antidepressants. Full discussion in our SSRI and ketamine post.
• "I have ADHD and take Adderall." Not a disqualifier. We just ask you to skip the stimulant the morning of your session so it has worn off by dosing time.
• "I have a history of trauma or PTSD." PTSD is one of the strongest indications for ketamine, not a contraindication. Ketamine has solid evidence for trauma-related conditions (Feder et al., American Journal of Psychiatry, 2021).
• "I drink wine sometimes." Occasional moderate drinking is not a disqualifier. Drinking the day of dosing is. Heavy daily drinking is a separate conversation.
• "I'm over 65." Age alone is not a contraindication. The starting dose is lower and we check balance before standing during the come-down, but otherwise it's the same protocol.
• "My blood pressure is a little high." Mild hypertension that is well-controlled on medication is not a disqualifier. Uncontrolled BP is.
• "I take birth control / thyroid meds / a statin." None of these interact with ketamine in any clinically meaningful way.

The general principle: a real contraindication is something with a clear, predictable, dangerous interaction with how ketamine acts on the body. Most things that feel concerning when you're researching are screening considerations, not disqualifiers.

Situational requirements for at-home treatment

Beyond medical conditions, a few circumstances make safe at-home treatment impossible regardless of your health:

• No peer supervisor available. We require every patient to have a trusted adult 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.
• No access to psychological support. Ketamine therapy works best as part of a broader treatment plan that includes some form of psychological support: formal psychotherapy, structured integration sessions, or at minimum a therapeutic relationship with a provider who can help you process what emerges. 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 rather than to treat a diagnosed condition, they are not an appropriate candidate. This is not a judgment; it is a matter of medical ethics and legal compliance.

How DK screens every patient

Every Discreet Ketamine intake includes:

1. A full medical history covering cardiovascular, neurologic, psychiatric, and substance-use background
2. A current medication list cross-checked for serotonergic, opioid, and CNS-depressant interactions
3. Recent blood pressure readings (we ask for at least two home readings on different days)
4. A psychiatric history covering bipolar spectrum, psychosis history, and trauma
5. A direct video consultation with Dr. Ben Soffer, the prescribing physician, before any prescription is written
6. A safety-environment check covering whether you have a sober adult monitor available for your first sessions and a quiet, low-fall-risk space to dose in

This is the same screening framework recommended in the Sanacora et al. APA consensus statement and the McIntyre et al. international expert opinion on ketamine and esketamine for treatment-resistant depression (American Journal of Psychiatry, 2021). It is not optional, and it is the reason at-home ketamine has the safety record it does when delivered properly. If you want a deeper dive into the safety architecture, our risks and side effects post covers what we monitor and why.

What if you have a contraindication?

A contraindication for at-home sublingual ketamine is not necessarily a contraindication for all ketamine treatment. Several pathways still exist:

• In-clinic IV ketamine under anesthesia monitoring: appropriate for some patients with cardiovascular risk who can be monitored continuously
• Treating the underlying condition first: uncontrolled BP can be treated and revisited; stabilized bipolar with a mood stabilizer can sometimes proceed
• Esketamine (Spravato) in a certified clinic: has different safety monitoring and may fit some patients
• Other rapid-acting treatments: repetitive TMS, ECT, or newer agents may be the better fit

When we identify a contraindication, we explain why and, where possible, suggest alternative approaches or steps that might make treatment possible in the future. We tell you directly and recommend the most appropriate alternative. We do not prescribe around safety concerns.

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, uncontrolled hypertension, active mania or untreated bipolar I, recent heart attack or stroke, severe liver disease, pregnancy or breastfeeding, and active substance use disorder involving dissociatives. Beyond those, several conditions require careful evaluation rather than automatic exclusion: stable bipolar II on a mood stabilizer, controlled cardiovascular disease, mild liver disease, history of substance use in remission, severe respiratory conditions, and certain medications. Every responsible at-home program screens for these before approving treatment.

What automatically disqualifies you from ketamine therapy?

The hard disqualifiers are: a known ketamine allergy, active psychosis or schizophrenia, uncontrolled hypertension (resting BP above ~160/100 mmHg), active mania or untreated bipolar I, recent heart attack or stroke, severe liver disease, active uncontrolled substance use disorder (particularly with dissociatives, opioids, or alcohol), increased intracranial pressure, severe untreated sleep apnea, pregnancy or breastfeeding without a compelling clinical reason, and inability to arrange a peer supervisor for at-home sessions. Conditions like stable bipolar, controlled cardiovascular disease, liver disease, and most medications require evaluation but don't automatically disqualify you.

What blood pressure is too high for ketamine?

A consistent resting BP above approximately 160/100 mmHg, or a history of hypertensive emergency, is an absolute contraindication for at-home ketamine. Between 140/90 and 160/100 is typically a "let's get this controlled first" conversation. Below 140/90 on or off medication is generally fine. Ketamine reliably raises blood pressure by 15-25 mmHg for 30-60 minutes after dosing, so we need a healthy baseline.

Can you take ketamine with bipolar disorder?

Stable bipolar II on a mood stabilizer (lithium, valproate, or lamotrigine) can usually be treated with careful screening and confirmation from your prescribing psychiatrist. Untreated bipolar I and anyone with manic or hypomanic symptoms in the past 90 days is not a candidate, because ketamine's rapid antidepressant action can trigger mania in unstable bipolar disorder.

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

Yes, generally. SSRIs and SNRIs are considered safe to combine with ketamine; serotonin syndrome from the combination is extremely rare. They work through different mechanisms (serotonin pathways vs. ketamine's glutamate/NMDA mechanism), and most patients continue their existing antidepressants throughout treatment. The medications that do conflict are MAOIs and tramadol. See our medication safety guide for the full list.

Does taking Adderall or other ADHD medication disqualify me?

No. We ask patients on stimulants to skip their morning dose on session days so the stimulant has worn off before ketamine dosing. This avoids stacking the cardiovascular effects of both drugs. After the session you resume your normal stimulant schedule the next day.

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.

Can I do ketamine if I have a history of substance abuse?

Often yes, if you are in stable remission for at least 12 months and the prior substance was not ketamine, PCP, or another dissociative. We have a longer screening conversation about home environment, support system, and relapse triggers. Active substance use disorder, and any active or recent ketamine use disorder, is a contraindication.

Will my age disqualify me from ketamine therapy?

No. We treat patients well into their 70s. We use a lower starting dose and pay extra attention to blood pressure, balance during the come-down, and any cognitive or fall-risk factors. Age alone is not a contraindication; the medical conditions that become more common with age are what we actually screen for.

Is ketamine therapy safe during pregnancy?

No. Ketamine crosses the placenta and is excreted in breast milk, and there are no controlled human safety data. We do not prescribe to anyone pregnant, actively trying to conceive, or breastfeeding. Patients on treatment are asked to use effective contraception throughout.

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 (Murrough et al., Am J Psychiatry, 2013, PMID 23982301; response rates have been similar across subsequent replications and meta-analyses). Response rates for anxiety, PTSD, and chronic pain are similar but variable. A thorough medical and psychiatric intake helps identify likely responders, but no provider can guarantee response in any individual.

How do I find out if I qualify?

The fastest way is the eligibility quiz. It takes about two minutes and covers the same screening I use on intake. If anything is unclear, you book a consultation and we go through it together on video before any prescription is written.

About the author

Dr. Ben Soffer, DO, is a board-certified physician and the founder of Discreet Ketamine. He has personally screened, treated, and followed thousands of at-home ketamine therapy patients across Florida and New Jersey. He writes about ketamine therapy from inside the consultation room: what actually comes up, what the evidence actually shows, and what patients deserve to know before deciding.

Take the 2-minute eligibility quiz →

References

1. Sanacora G, Frye MA, McDonald W, Mathew SJ, Turner MS, Schatzberg AF, et al. A Consensus Statement on the Use of Ketamine in the Treatment of Mood Disorders. JAMA Psychiatry. 2017;74(4):399-405. PubMed: 28249076 American Psychiatric Association consensus document defining the safety screening framework for psychiatric ketamine use, including absolute and relative contraindications.

2. Short B, Fong J, Galvez V, Shelker W, Loo CK. Side-effects associated with ketamine use in depression: a systematic review. Lancet Psychiatry. 2018;5(1):65-78. PubMed: 28757132 Systematic review confirming that subanesthetic-dose ketamine adverse effects cluster in patients with pre-existing cardiovascular instability and are otherwise mild and transient.

3. Diazgranados N, Ibrahim L, Brutsche NE, Newberg A, Kronstein P, Khalife S, et al. A randomized add-on trial of an N-methyl-D-aspartate antagonist in treatment-resistant bipolar depression. Arch Gen Psychiatry. 2010;67(8):793-802. PubMed: 20679587 RCT establishing efficacy of ketamine in stable bipolar depression on mood stabilizers, the basis for cautious case-by-case clearance of bipolar II patients.

4. Grunebaum MF, Ellis SP, Keilp JG, Moitra VK, Cooper TB, Marver JE, et al. Ketamine versus midazolam in bipolar depression with suicidal thoughts: A pilot midazolam-controlled randomized clinical trial. Bipolar Disord. 2017;19(3):176-183. PubMed: 28452409 Midazolam-controlled trial showing rapid anti-suicidal effect of ketamine in bipolar depression, with safety screening that excluded actively manic and unmedicated bipolar I patients.

5. Feder A, Costi S, Rutter SB, Collins AB, Govindarajulu U, Jha MK, et al. A Randomized Controlled Trial of Repeated Ketamine Administration for Chronic Posttraumatic Stress Disorder. Am J Psychiatry. 2021;178(2):193-202. PubMed: 33397139 RCT establishing PTSD as a strong indication for ketamine therapy, not a contraindication.

6. McIntyre RS, Rosenblat JD, Nemeroff CB, Sanacora G, Murrough JW, Berk M, et al. Synthesizing the Evidence for Ketamine and Esketamine in Treatment-Resistant Depression: An International Expert Opinion on the Available Evidence and Implementation. Am J Psychiatry. 2021;178(5):383-399. PubMed: 33726522 International expert consensus on ketamine and esketamine implementation, including the safety screening framework used at Discreet Ketamine.

7. Murrough JW, Iosifescu DV, Chang LC, Al Jurdi RK, Green CE, Perez AM, et al. Antidepressant efficacy of ketamine in treatment-resistant major depression: a two-site randomized controlled trial. Am J Psychiatry. 2013;170(10):1134-1142. PubMed: 23982301 Two-site RCT establishing the ~50-70% response rate for ketamine in treatment-resistant depression.

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