Ketamine Infusion Therapy for Chronic Pain

Ketamine is a medication I've worked with for a long time — first as an anesthetic adjunct in procedural settings, now as a treatment for patients whose chronic pain has not responded to conventional approaches. It's also one of the most misunderstood options I offer.

Patients hear "ketamine" and immediately think of recreational misuse, or they've read something online and arrived expecting a complete cure. The reality is more nuanced. Ketamine infusion therapy, delivered at sub-anesthetic doses under proper medical supervision, has genuine and sometimes dramatic benefit for specific chronic pain conditions. But not every patient responds, and I think it's important to have that conversation honestly before we start.

Dr. Edward Rubin offers ketamine infusion therapy at his Long Island practice as part of a comprehensive, individualized pain management approach. Every infusion is medically supervised and tailored to each patient's specific diagnosis, pain history, and treatment goals.

What Is Ketamine?

Ketamine is an NMDA (N-methyl-D-aspartate) receptor antagonist. At sub-anesthetic infusion doses, it does not put patients to sleep — instead, it interrupts the way pain signals are processed in the central nervous system.

Chronic pain conditions often involve a process called central sensitization — the central nervous system becomes "wound up," amplifying pain signals far beyond what the original injury or condition would produce. Ketamine works directly on this mechanism, essentially resetting overactive pain pathways in the brain and spinal cord.

This is why ketamine can provide meaningful relief even when opioids, anti-inflammatory medications, nerve blocks, and other therapies have failed.

Conditions Treated with Ketamine Infusions

Dr. Rubin uses ketamine infusion therapy for a range of complex and treatment-resistant conditions, including:

• Complex Regional Pain Syndrome (CRPS) — Type I and Type II; ketamine is one of the most evidence-supported treatments for this condition
• Fibromyalgia — Central sensitization is a core feature; ketamine interrupts this cycle
• Chronic neuropathic pain — Including diabetic neuropathy, post-herpetic neuralgia, and nerve injury pain
• Failed back surgery syndrome — Persistent pain after one or more spinal surgeries
• Phantom limb pain — After amputation
• Migraine and chronic daily headache — Select refractory cases
• Cancer pain — When conventional opioid therapy is insufficient or causing intolerable side effects
• Post-surgical chronic pain — Thoracotomy pain, mastectomy pain, and other post-surgical syndromes

What to Expect During a Ketamine Infusion

Before the infusion: Dr. Rubin will review your full medical history, current medications, prior treatments, and imaging studies. A comprehensive evaluation ensures ketamine is appropriate for you and that we have clear goals for your series of infusions.

During the infusion: You will receive an IV line, and the ketamine is delivered slowly over 40 minutes to 4 hours depending on the protocol. You remain awake throughout. Some patients experience mild perceptual changes — a floating sensation, altered sense of time, or visual effects — which resolve fully when the infusion ends. Vitals are monitored continuously throughout.

After the infusion: You will need a driver. Most patients feel fine within an hour, though some report mild fatigue or grogginess for several hours. No driving or operating heavy machinery for the rest of the day.

The series: A single infusion rarely produces durable results. Research and clinical experience both show that a series — typically 3 to 6 infusions over 2–3 weeks — produces significantly more sustained relief. Some patients return for maintenance infusions every few months to sustain the benefit.

How Effective Is Ketamine for Chronic Pain?

Response rates vary by condition. For CRPS, studies have reported significant pain reduction in 70–80% of patients following a course of infusions. For other neuropathic conditions, response rates of 50–70% are commonly reported in the literature.

Relief after ketamine infusions is often qualitatively different from what opioids provide — less sedating, with improvements in mood, function, and sleep alongside the pain reduction. Some patients describe it as the first time in years they've felt like themselves.

That said, ketamine is not a cure. Some patients don't respond. Some who respond initially find the effect fades over time. Dr. Rubin will discuss your specific likelihood of benefit based on your diagnosis and history — and if it doesn't work, there are other directions to explore.

Is Ketamine Safe?

At sub-anesthetic doses under proper medical supervision, ketamine infusion therapy has a well-established safety profile. The main side effects during the infusion are the perceptual changes described above, which are temporary and expected.

Ketamine is not appropriate for patients with certain psychiatric conditions (including untreated schizophrenia or active psychosis), uncontrolled hypertension, or a personal history of ketamine abuse. Dr. Rubin screens all patients carefully before recommending infusion therapy.

Frequently Asked Questions

Does insurance cover ketamine infusion therapy? Most insurance plans — including Medicare — do not currently cover ketamine infusions for chronic pain, as this is considered off-label use. Coverage determinations are still evolving. Our office can provide documentation to support self-pay reimbursement requests to your insurer, though approval is not guaranteed.

Will I be asleep or unconscious? No.

Sub-anesthetic doses don't cause unconsciousness. You'll be awake and aware the entire time, though you may notice mild perceptual effects that fade when the infusion ends. Many patients rest comfortably and some even sleep lightly during the session.

Can I take my regular medications on the day of the infusion? This depends heavily on your regimen. Benzodiazepines and high-dose opioids can reduce ketamine's effectiveness and are often adjusted before the series begins. Dr. Rubin will give you specific pre-procedure instructions at your consultation — don't make any medication changes on your own before we've reviewed your full medication list together.

How soon will I know if it's working? Some patients notice improvement after the first or second infusion. Others need to complete the full series before they can accurately judge their response. We track pain levels throughout the treatment course so you're never left guessing where things stand.

What if ketamine doesn't help? We regroup and look at what's next. Depending on your diagnosis and what's been tried already, that might mean spinal cord stimulation, intrathecal pump therapy, or another approach suited to your specific condition. One treatment not working does not mean you've exhausted your options.

Schedule a Ketamine Consultation

Ketamine infusion therapy is offered at our Lake Success office and is reserved for patients who have completed a thorough evaluation with Dr. Rubin. Call 516-492-3100 or use the form below to request a consultation.