TLDR
Ketamine infusion therapy is generally considered for people with chronic pain that has not responded well to more conventional treatments. Good candidates often have nerve-related pain conditions such as CRPS, neuropathic pain, or certain forms of persistent post-surgical pain. Before scheduling an infusion, a pain physician will review your medical history, current medications, blood pressure, heart health, and any history of psychosis or substance use. Uncontrolled hypertension, active psychosis, unstable heart disease, and pregnancy are the most common reasons someone is not cleared. You do not need a psychiatric diagnosis to qualify for ketamine when it is being used for pain. If you are unsure whether you’re a candidate, a consultation is the only way to find out, since eligibility depends on your specific history rather than a checklist you can complete on your own.
Why People Start Asking About Ketamine in the First Place
Most patients who ask us about ketamine did not arrive at it casually. They have usually been through a long stretch of treatments that helped a little, or helped for a while, or did not help at all. Physical therapy. Nerve blocks. Gabapentin or duloxetine. Maybe injections that took the edge off for a few weeks.
Ketamine tends to come up when pain has become neuropathic, meaning the nervous system itself has become part of the problem rather than just the messenger. That shift is what makes ketamine interesting to pain physicians. It works on NMDA receptors, which are involved in a process called central sensitization, where the spinal cord and brain start amplifying pain signals that should have quieted down long ago.
That mechanism is also why ketamine is not right for everyone. If your pain is mechanical and structural, something like a compressed nerve root from a herniated disc, the more direct answer might be an epidural steroid injection or a microdiscectomy, not an infusion.
The Pain Conditions Most Commonly Considered
There is no official master list that says who qualifies. What exists instead is a body of clinical evidence and consensus guidance that points toward certain conditions responding better than others.
The strongest evidence supports ketamine infusions for complex regional pain syndrome. Consensus guidelines from the American Society of Regional Anesthesia and Pain Medicine found the evidence for CRPS to be stronger than for most other chronic pain conditions. If you have been diagnosed with CRPS, you are among the patients most likely to be considered a reasonable candidate.
Other conditions that come up frequently:
- Neuropathic pain, including diabetic neuropathy and post-herpetic neuralgia
- Persistent post-surgical pain, especially after spinal surgery
- Phantom limb pain
- Central pain from spinal cord injury
- Fibromyalgia, though the evidence here is more mixed
- Refractory pain in patients who have developed opioid tolerance
Conditions where ketamine is generally not the first thing we reach for include straightforward sciatica, spinal stenosis, sacroiliac joint pain, and arthritis. These usually have clearer structural targets, and treatments like a sacroiliac joint injection or SI joint fusion address the actual source rather than the way your nervous system is processing it.
The “Have You Tried Everything Else” Question
Almost every ketamine screening includes some version of this. It is not a gatekeeping exercise designed to make you jump through hoops. It exists because ketamine is a more involved treatment than most alternatives, requiring monitored infusion time, and it makes clinical sense to try lower-burden options first.
What counts as having tried other things varies. Generally we want to see that you have made a reasonable attempt at:
- At least one or two medication classes appropriate to your condition
- Physical therapy or a structured rehab program, if your condition allows it
- Interventional options that fit your diagnosis, such as nerve blocks or injections
- Neuromodulation, in some cases, though this is not required
Neuromodulation deserves a note here. For some patients, a spinal cord stimulator or peripheral nerve stimulation offers longer-lasting relief than repeated infusions, because the device keeps working between visits. Part of a good consultation is figuring out whether you are a better fit for one path or the other, or both.
Medical Conditions That Can Disqualify You
This is the part patients want the clearest answer on, so here it is plainly.
Absolute or near-absolute contraindications:
- Active, uncontrolled psychosis or a diagnosis of schizophrenia
- Uncontrolled high blood pressure
- Unstable angina or a recent heart attack
- Increased intracranial pressure
- Pregnancy
- Severe liver disease
- Known allergy to ketamine
Conditions requiring careful evaluation but not automatic exclusion:
- Well-controlled hypertension
- History of substance use disorder, particularly involving ketamine or dissociatives
- Prior significant psychiatric hospitalization
- Sleep apnea
- Elevated thyroid hormone levels
- Certain arrhythmias
- Glaucoma or elevated eye pressure
- History of severe nausea with anesthesia
Blood pressure gets special attention because ketamine reliably raises it during the infusion. In a healthy cardiovascular system that increase is tolerated fine. If your pressure is already running high before you sit down, the margin gets uncomfortable. Many patients who are initially deferred come back three months later with better-controlled pressure and get cleared.
Medications That Complicate Things
Bring your complete medication list to your consultation, including supplements and anything you take occasionally. A few interactions matter:
Benzodiazepines may blunt some of ketamine’s effects, and there is reasonable evidence for this in the mood literature. For pain, the picture is less clear, but many physicians still ask patients to discuss timing or tapering with the prescribing doctor first. Never stop a benzodiazepine on your own.
Lamotrigine works partly by dampening glutamate release, which may work against ketamine’s mechanism.
Opioids do not prevent you from receiving ketamine. In fact, one reason patients pursue ketamine is to reduce opioid requirements. But dosing may be adjusted, and you should be honest about how much you actually take.
Stimulants and thyroid medication can add to the blood pressure and heart rate effects and may need timing adjustments.
What Actually Happens at a Screening Visit
A ketamine consultation at our NYC practice is not a quick yes or no. Expect roughly 45 minutes covering:
A full pain history, including what your pain feels like. Burning, electric, and shooting descriptors point toward neuropathic pain, which matters for predicting response.
A treatment history, so we understand what you have already tried and how it went.
A medical and psychiatric history. The psychiatric questions are safety questions, not judgment. Ketamine produces dissociative effects, and we need to know whether that is likely to be difficult for you.
Vital signs, always including blood pressure, sometimes with an EKG depending on your age and cardiac history.
A conversation about expectations. This one gets skipped too often. Ketamine is not a cure. Response rates in chronic pain vary widely across studies, relief is usually partial rather than complete, and duration varies from days to months. If you walk in expecting your pain to disappear permanently, you will be disappointed even by a good outcome.
Age, Insurance, and the Practical Questions
Age is not a hard cutoff on either end. Older adults are often started at lower doses with closer monitoring. Adolescents are treated rarely and only in specific circumstances.
Insurance is the more common practical barrier. Ketamine for chronic pain is used off-label, meaning the FDA has approved ketamine as an anesthetic but not specifically for chronic pain. Off-label prescribing is legal, common, and often evidence-based across all of medicine. But insurers frequently decline to cover it, so ask about cost during your consultation rather than after your first infusion.
You will also need a ride home. You cannot drive for the rest of the day, and in the city that usually means arranging a friend or a car service in advance.
Do You Need a Psychiatric Diagnosis?
No. This confusion comes from esketamine, the nasal spray version, which is FDA-approved specifically for treatment-resistant depression. That is a different formulation with a different approval pathway.
IV ketamine used for chronic pain does not require a mood disorder diagnosis. Plenty of our pain patients have no psychiatric history at all. If you do also have depression or anxiety, which is extremely common alongside long-term pain, that is worth mentioning during screening. It changes how we monitor you and sometimes what we hope to see.
What to Do If You Are Not Cleared
Being deferred is not always permanent. Blood pressure gets managed. Medications get adjusted. Cardiac clearance gets obtained. Many patients who hear “not yet” become candidates within a few months.
And if ketamine is genuinely not the right fit, that answer still moves you forward. It might redirect you toward neuromodulation, or toward a targeted procedure like Minuteman lumbar fusion if your pain has a structural driver that has been missed. A good pain practice does not just tell you no. It tells you what comes next.
Talk to a Pain Specialist Who Will Give You a Straight Answer
You cannot determine your own eligibility from an article, and any clinic that offers infusions without a real screening should worry you. Our interventional pain physicians evaluate each patient individually, and if ketamine is not right for you, we will say so and explain what is.
Schedule a consultation to talk through whether ketamine therapy makes sense for your situation.
