Ketamine Korner: Edition 6
Ketamine Korner is a bi-weekly newsletter exploring advances in ketamine therapy, originally started by Mind Pain Relief Institute Co-Founder Dr. Rohit Aiyer.
Each edition is republished with permission from Dr. Aiyer.
Latest Research Highlight:
CRPS has long been associated with central sensitization, a process in which the nervous system becomes persistently hyperexcitable. Because NMDA receptor activation plays a key role in this mechanism, ketamine has been studied as a potential intervention for refractory CRPS pain.
One of the most cited randomized, placebo-controlled trials was published in Pain in 2009 by Sigtermans and colleagues. In this study, patients with long-standing CRPS type I received a continuous low-dose intravenous ketamine infusion over several days. Compared with placebo, the ketamine group experienced significant reductions in pain intensity, with benefits lasting several weeks after treatment. Notably, while pain scores improved, functional outcomes did not change substantially—highlighting the complexity of treating CRPS beyond pain relief alone.
In the same year, a randomized outpatient trial led by Schwartzman et al., published in Pain Medicine, evaluated subanesthetic IV ketamine administered over multiple days in patients with refractory CRPS. The ketamine group demonstrated statistically significant improvements in pain measures compared to placebo, with some patients reporting sustained benefit for up to three months.
More recent systematic reviews and narrative analyses (2013–2023) have consistently concluded that ketamine can provide short- to intermediate-term analgesia in CRPS, particularly in patients who have failed conventional therapies. However, these reviews also emphasize variability in dosing protocols, duration of benefit, and side-effect profiles, underscoring the need for individualized treatment planning and careful monitoring.
A Brief History of Ketamine in CRPS Treatment:
Early Neuropathic Pain Research: Ketamine’s use in CRPS emerged from earlier work in the 1990s and early 2000s demonstrating its efficacy in neuropathic pain states driven by central sensitization. Researchers hypothesized that NMDA receptor antagonism could interrupt the “wind-up” phenomenon seen in chronic pain.
Formal Clinical Trials: By the late 2000s, controlled trials specifically targeting CRPS began to appear. The 2009 studies marked an important shift—from anecdotal use toward evidence-based application—establishing ketamine as one of the few interventions shown to meaningfully reduce pain in refractory CRPS populations.
Evolving Clinical Practice: In the 2010s, ketamine infusion protocols became more standardized, and professional societies began issuing consensus guidelines on its use in chronic pain. These guidelines generally characterize the evidence for CRPS as moderate, recommending ketamine primarily for severe, treatment-resistant cases within experienced clinical settings.
Current Perspective: Today, ketamine is viewed not as a cure for CRPS, but as a potential therapeutic window—a way to reduce pain intensity enough to allow engagement in physical therapy, occupational therapy, and functional rehabilitation, which remain essential for long-term outcomes.
Mythbuster:
Myth: Ketamine “cures” CRPS and replaces the need for rehabilitation.
Reality:
Pain Reduction, Not Cure: Controlled trials show that ketamine can significantly reduce pain in CRPS, but it does not reverse the condition or reliably restore function on its own.
Time-Limited Benefit: Analgesic effects typically last weeks to months, not indefinitely, and repeat treatments may be required in selected patients.
Best Used as Part of a Plan: Evidence and expert consensus support ketamine as an adjunct—most effective when paired with physical therapy, desensitization techniques, and multidisciplinary care.
Key Takeaway:
Ketamine is one of the few treatments with randomized trial evidence for reducing pain in refractory CRPS. While it is not a stand-alone solution, in carefully selected and closely monitored patients, it can provide meaningful relief and create an opportunity for functional recovery strategies to take hold.
As the science evolves, so does our understanding of ketamine’s place in modern psychiatry. Staying informed helps us separate fact from myth and see where the future of treatment may lead. Until next time, stay curious and engaged with the possibilities ahead.