Ketamine Infusion Therapy for Chronic Pain After an Accident

James Wong — Founder & Pharmacist, LienScripts | February 10, 2026 | 8 min read

Ketamine infusion therapy is emerging as a powerful option for PI patients with CRPS, refractory chronic pain, and central sensitization. Learn how pharmacy liens make this treatment accessible when insurance says no.

What Is Ketamine Infusion Therapy?

Ketamine is an NMDA (N-methyl-D-aspartate) receptor antagonist that has been used as a dissociative anesthetic since the 1960s. In recent decades, sub-anesthetic doses — doses far too low to induce unconsciousness — have become a recognized treatment for severe chronic pain conditions, particularly those that have not responded to conventional medications.

For personal injury patients, ketamine infusion therapy is increasingly prescribed by pain management specialists to address a cluster of conditions that commonly follow traumatic injuries: complex regional pain syndrome (CRPS), central sensitization, refractory neuropathic pain, and opioid-resistant chronic pain syndromes.

Understanding how ketamine works — and why insurance routinely denies it — is essential for personal injury attorneys and patients navigating recovery after an accident.

CRPS and Central Sensitization: The PI Connection

Two of the most compelling indications for ketamine therapy in personal injury cases are CRPS and central sensitization.

Complex Regional Pain Syndrome (CRPS) is a debilitating neuropathic condition that can develop after relatively minor injuries — a sprained wrist, a bone fracture, or soft tissue trauma from a car accident. The hallmark is disproportionate, burning pain that spreads beyond the original injury site, often accompanied by skin color and temperature changes, swelling, and extreme sensitivity to touch. CRPS is well-documented in the PI literature and can generate substantial special damages in a claim.

Central sensitization refers to a neurological state in which the central nervous system becomes hypersensitive to pain signals. After a traumatic injury, ongoing nociceptive input can "wind up" the spinal cord and brain, lowering the pain threshold and amplifying signals that would ordinarily be perceived as mild. This is the mechanism behind widespread post-accident pain, allodynia (pain from light touch), and chronic widespread pain syndromes that outlast the original tissue injury.

Ketamine disrupts both processes. By blocking NMDA receptors — which play a central role in wind-up and central sensitization — sub-anesthetic ketamine infusions can "reset" abnormal pain processing and provide relief lasting weeks to months after the infusion series is complete.

[!KEY] For PI attorneys, a diagnosis of CRPS or central sensitization supported by pain specialist documentation is a significant damages amplifier. Ketamine infusion records and pharmacy lien documentation become important components of the demand package.

FDA Status, Off-Label Use, and Compounded Ketamine

The FDA has approved ketamine (racemic) as an anesthetic agent. Its use for chronic pain is considered off-label — meaning it is a legitimate medical practice but one the FDA has not formally reviewed for this specific indication. This distinction matters enormously for insurance coverage, because off-label use is one of the most common grounds for claim denial.

In addition to IV infusion, pain management physicians sometimes prescribe:

• Oral compounded ketamine — typically as a low-dose lozenge or capsule for home use between infusion sessions
• Intranasal compounded ketamine — a spray formulation providing rapid relief for breakthrough pain episodes
• Topical compounded ketamine cream — applied directly to painful areas for localized neuropathic pain, sometimes combined with other agents such as gabapentin or amitriptyline

These compounded forms are prepared by compounding pharmacies and are not commercially available as FDA-approved products. They are prescribed by licensed physicians and require a valid patient-specific prescription.

Esketamine (Spravato) vs. IV Ketamine

Esketamine (brand name Spravato) is the S-enantiomer of ketamine and holds FDA approval for treatment-resistant depression and major depressive disorder with acute suicidal ideation. It is administered as a nasal spray in a supervised clinical setting.

Some PI patients — particularly those who develop post-traumatic depression or comorbid chronic pain with a depressive component — may be appropriate candidates for Spravato. However, Spravato's approval is psychiatric, not pain-specific, and its use in PI-related pain management is typically off-label.

IV ketamine infusions remain the most studied and widely used modality for refractory chronic pain. Protocols typically consist of a series of four to six infusions over two weeks, with maintenance infusions every one to three months depending on the patient's response.

[!SOURCE] The American Society of Regional Anesthesia and Pain Medicine (ASRA) and the American Academy of Pain Medicine published consensus guidelines on ketamine infusions for chronic pain, providing a clinical framework that supports physician prescribing decisions. See: Cohen SP et al., "Consensus Guidelines on the Use of Intravenous Ketamine Infusions for Chronic Pain," Regional Anesthesia and Pain Medicine (2018).

Why Insurance Denies Ketamine Therapy in PI Cases

Private health insurance routinely denies ketamine infusion therapy for chronic pain on several grounds:

1. Off-label use — no FDA approval for chronic pain
2. Lack of medical necessity determination — insurers may dispute that a less expensive alternative has been adequately tried
3. Step therapy requirements — policies may require documented failure of multiple prior treatments before approving more intensive interventions
4. No in-network providers — ketamine infusion clinics are rarely in-network, leading to out-of-network benefit disputes or outright denials

In personal injury cases, this problem is compounded because the at-fault party's liability insurer is not a health insurer and has no obligation to pre-authorize or cover any treatment. MedPay and PIP coverage, when available, have policy limits that are typically exhausted before ketamine therapy is needed.

The result: a PI patient with documented CRPS or central sensitization, for whom a pain management specialist has recommended ketamine infusions, cannot access the treatment without paying out of pocket — unless they have access to a pharmacy lien.

How Pharmacy Liens Cover Ketamine Therapy

A pharmacy lien is a contractual arrangement in which a pharmacy or pharmacy lien program provides medications and certain treatment-adjacent services to a personal injury patient on credit, with repayment deferred until the case resolves from the settlement or judgment.

For ketamine-related prescriptions — including compounded oral, intranasal, or topical ketamine formulations — a pharmacy lien program can fill and dispense the prescription without requiring upfront payment from the patient. The lien is secured against the anticipated settlement proceeds.

Importantly, pharmacy liens do not typically cover the IV infusion procedure itself (which is a medical service). However, they can cover:

• Compounded ketamine preparations (oral, intranasal, topical)
• Adjunct medications prescribed alongside ketamine (e.g., clonidine, ondansetron for nausea prophylaxis, benzodiazepines for pre-infusion anxiety)
• Home pain management medications prescribed as part of the overall ketamine protocol

[!KEY] Attorneys should request complete prescription records from the compounding pharmacy as part of case preparation. A well-documented ketamine protocol — with prescriptions, dispensing records, and physician notes explaining medical necessity — strengthens the argument that the patient's injuries were serious and required advanced intervention.

Documentation for the Demand Package

When a PI case involves ketamine therapy, the demand package should include:

• Pain specialist records documenting the diagnosis (CRPS, central sensitization, refractory neuropathic pain), the recommendation for ketamine, and the clinical rationale
• Insurance denial letters showing that conventional coverage was sought and refused
• Infusion clinic records with dates, dosing, and patient response notes
• Pharmacy lien records for any compounded ketamine prescriptions, showing the lien amount and the dispensing pharmacy's involvement
• A treating physician narrative connecting the accident, the injury mechanism, the development of chronic pain, and the medical necessity of ketamine therapy

This documentation creates a coherent narrative that justifies both the treatment and its cost, supporting full compensation for the medication and treatment expenses incurred.

Related Resources

• Compound Medications in Personal Injury Cases
• Spravato (Esketamine) for Depression After a Personal Injury
• Pain Management Doctor and Pharmacy Lien Coordination
• What Is a Pharmacy Lien?
• Specialty Medications in Personal Injury Cases