Ketamine Troches vs. Infusion Therapy for Chronic Pain

Ketamine troches and ketamine infusion therapy are both used off-label to manage chronic pain, but they differ in bioavailability, setting, cost, and how much research supports pain-specific use. Intravenous (IV) infusion delivers ketamine directly into the bloodstream in a monitored clinical setting and has the larger evidence base for pain conditions such as complex regional pain syndrome (CRPS) and neuropathic pain. Ketamine troches, compounded lozenges dissolved under the tongue, offer a lower-intensity, at-home option that some prescribers use for maintenance between infusions or when infusion access is limited, though far less pain-specific research exists for the troche route.

Neither use is FDA-approved for chronic pain. The U.S. Food and Drug Administration (FDA), the federal agency responsible for approving drugs as safe and effective for specific uses, has approved only one ketamine-derived product, esketamine (Spravato), and that approval covers treatment-resistant depression, not pain. Learn more from the FDA's announcement on esketamine approval. Ketamine troches and IV ketamine infusions for chronic pain are both prescribed off-label, meaning a licensed prescriber applies an approved anesthetic drug outside its FDA-labeled indication based on clinical judgment. This article is educational and not medical advice, decisions about which route fits your pain condition belong with your prescriber.

How Each Method Works

Both methods rely on ketamine's action at the NMDA receptor, a glutamate receptor in the brain and spinal cord involved in pain signaling and central sensitization, the process by which the nervous system becomes more reactive to pain over time. The two delivery methods diverge sharply in how much of the drug reaches the bloodstream and how quickly.

IV Ketamine Infusion

An IV infusion delivers ketamine directly into a vein, so essentially all of the administered dose reaches circulation (100% bioavailability). Infusions for chronic pain are typically given in a hospital outpatient unit, infusion center, or pain clinic over roughly 40 minutes to several hours, with continuous monitoring of blood pressure, heart rate, and oxygen levels throughout the session.

Ketamine Troches (Sublingual)

A ketamine troche is a compounded lozenge that dissolves under the tongue, allowing the drug to absorb through the oral mucosa (the lining of the mouth) and partly bypass the liver's first-pass metabolism that oral capsules undergo. Even so, sublingual bioavailability stays well below IV levels, and onset is slower, typically starting within 10 to 20 minutes and building to a peak over the following hour. See the ketamine troche onset, peak, and duration timeline for a fuller breakdown. Troches are dosed at home following a written prescriber protocol; the full mechanics of the treatment are covered in the sublingual ketamine therapy guide.

What the Research Actually Shows

The strongest published evidence for ketamine in chronic pain comes from IV infusion studies. The American Society of Regional Anesthesia and Pain Medicine (ASRA Pain Medicine), a professional medical society for pain physicians, worked with partnering organizations to publish consensus guidelines on IV ketamine infusions for chronic pain, reviewing evidence across conditions including CRPS, fibromyalgia, and neuropathic pain. You can review this body of research through PubMed-indexed literature on IV ketamine consensus guidelines for chronic pain. The guidelines describe short-to-moderate-term pain relief in some patients, particularly with CRPS and neuropathic pain, while noting that evidence quality varies by condition and dose, and that infusions do not work for everyone.

Ketamine troches have not been studied for chronic pain with anywhere near the same volume of research. Most published data on sublingual and oral ketamine focuses on pharmacokinetics, how the drug is absorbed and metabolized, and on depression, not pain-specific outcomes. Pharmacokinetic research indexed on PubMed shows sublingual ketamine reaches lower and more variable blood concentrations than IV administration, largely because of first-pass liver metabolism that converts much of the dose into norketamine, an active metabolite with its own effects. You can review this pharmacokinetic literature via PubMed-indexed sublingual ketamine bioavailability studies. Prescribers who use troches for pain are generally extrapolating from depression and general ketamine pharmacology research, not from pain-specific trials of the troche route itself, so it's worth asking your prescriber directly what evidence supports troches for your particular diagnosis.

Who Each Option Tends to Fit

IV ketamine infusion therapy tends to fit patients who need clinically supervised dosing, have a diagnosis with more infusion-specific research behind it, or are early in treatment and need close monitoring while a prescriber assesses response. Ketamine troches tend to fit patients who are already stabilized on a known ketamine regimen, need a lower-friction way to continue treatment between infusions, or don't have practical access to an infusion clinic and are working with a prescriber willing to manage at-home dosing with safety guardrails in place.

Cost is often part of this decision. IV infusions are typically billed per session at an infusion clinic and can require several sessions in an initial series, while troches are usually filled through a compounding pharmacy on a monthly prescription basis. For typical price ranges and what drives cost up or down, see how much ketamine troches cost.

Neither route is meant for self-directed use, both require a licensed prescriber to evaluate your diagnosis, set a monitoring plan, and adjust the protocol over time. If you're weighing troches against other delivery forms, related comparisons include subcutaneous ketamine vs troches patient outcomesSpravato vs ketamine troches effectiveness, and ketamine troches vs oral capsules for PTSD treatment outcomes.

Finding a Prescriber Who Can Guide This Decision

Because troches and infusions carry different monitoring requirements and evidence bases, this decision works best with a prescriber who can evaluate both options against your specific pain diagnosis rather than defaulting to whichever route their practice offers. Some telehealth practices coordinate troche prescriptions with a compounding pharmacy and periodic check-ins, which can work well for patients who are stabilized or lack local infusion access, but a prescriber should still confirm that a telehealth-managed troche protocol is appropriate for your condition before you start.