Low Dose Ketamine for Chronic Pain: What is the Evidence?

Ketamine clinics have exploded worldwide, offering low-dose intravenous infusions for chronic pain patients who've run out of options. But is this practice actually backed by evidence, or has off-label use outpaced the science? In this episode of the PainExam Podcast, Dr. David Rosenblum reviews the current literature on subanaesthetic-dose ketamine infusions (SDKIs) for chronic pain, drawing on the 2023 British Journal of Pain review by Harry M. Griffiths, "Low-dose ketamine infusions for chronic pain management: Does this qualify as evidence-based practice?" Topics covered: Why conventional analgesics (opioids, anticonvulsants, antidepressants) fail in 60–70% of chronic pain patients How ketamine works as an NMDA receptor antagonist, and why that mechanism is likely an oversimplification Typical SDKI dosing (~0.35–0.5 mg/kg) versus anesthetic dosing, and why the IV route dominates the evidence base What the meta-analyses actually show: modest, time-limited pain reduction (mean difference around -1.83 on a 0–10 scale) with higher efficacy but more side effects at higher doses Key trials — Corriger et al.'s 1-year follow-up (256 patients), Orhurhu et al.'s systematic review and meta-analysis, and smaller RCTs in CRPS, fibromyalgia, and ischemic limb pain Common side effects (nausea, psychomimetic symptoms) versus rare but serious adverse events (hepatic, cardiac, urogenital) — and how dose and premedication with clonidine/midazolam affect risk Why blinding failure (up to 93% of patients correctly guessing their treatment in one trial) may be inflating reported effect sizes The absence of standardized protocols, guidelines, or a clear "exit strategy" for patients on long-term SDKI therapy What needs to happen next: larger multicenter RCTs, ketamine clinic registries, and better outcome measures beyond simple pain scores Bottom line: SDKIs offer a promising but still under-evidenced option for refractory chronic pain — reserved for the right patient, with modest expectations and careful monitoring. Reference: Griffiths HM. Low-dose ketamine infusions for chronic pain management: Does this qualify as evidence-based practice? Br J Pain. 2023;17(5). https://journals.sagepub.com/doi/full/10.1177/20494637231182804 Show Image About the Host David Rosenblum, MD is Director of Pain Management at Maimonides Medical Center and Co-Owner/Clinic Director of AABP Integrative Pain Care and Wellness in Brooklyn, NY. Dual board-certified in Anesthesiology and Pain Medicine, he is a co-author of the ASIPP Peripheral Nerve Stimulation (PNS) guidelines and a widely recognized educator in regenerative pain medicine (PRP, BMAC, amniotic therapies). As founder of NRAP Academy, he has trained 3,500+ physicians for pain board certification since 2008, and hosts the PainExam, AnesthesiaExam, and PMRExam podcasts. He has been named a New York Magazine "Top Doctor" from 2016–2026. Living with chronic pain? Dr. Rosenblum sees patients for interventional and regenerative pain treatment — including epidurals, nerve blocks, spinal cord & peripheral nerve stimulation, and PRP/BMAC — at his Brooklyn, NY office. Visit RosenblumPain.com for more information. For Physicians & APPs — Continue Your Education: CME Course Calendar: https://www.nrappain.org/pages/upcoming-pain-management-conferences Virtual Pain Fellowship: https://www.nrappain.org/bundles/Virtual-Pain-Fellowship PainExam Board Prep: https://www.nrappain.org/pages/pain-management-cme-couåçrses This episode is brought to you by NRAP Academy and PainExam — visit www.NRAPpain.org for CME in neuromodulation, regional anesthesia, and pain medicine.