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, 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 with higher efficacy but more side effects at higher doses
• - Key trials, including Corriger et al.'s 1-year follow-up (256 patients) and Orhurhu et al.'s systematic review and meta-analysis
• - Common side effects (nausea, psychomimetic symptoms) versus rare but serious adverse events, and how premedication with clonidine/midazolam affects risk
• - Why blinding failure may be inflating reported effect sizes
• - The absence of standardized protocols, guidelines, or a clear "exit strategy" for long-term SDKI therapy

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

 

This episode is brought to you by NRAP Academy and PainExam - visit www.NRAPpain.org for CME in neuromodulation, regional anesthesia, and pain medicine.