Efficacy and Safety of Ketamine in Patients with Complex Regional Pain Syndrome

Abstract

Despite being a recognized clinical entity for over 140 years, complex regional pain syndrome (CRPS) remains a difficult-to-treat condition. While there have been multiple therapies explored in the treatment of CRPS, NMDA antagonists such as ketamine continue to hold significant interest because of their potential ability to alter the central sensitization noted in chronic pain states. The objective of this review is to identify published literature for evidence of the efficacy and safety of ketamine in the treatment of CRPS. PubMed and the Cochrane Controlled Trials Register were searched (final search 26 May 2011) using the MeSH terms 'ketamine', 'complex regional pain syndrome', 'analgesia' and 'pain' in the English literature. The manuscript bibliographies were then reviewed to identify additional relevant papers. Observational trials were evaluated using the Agency for Healthcare Research and Quality criteria; randomized trials were evaluated using the methodological assessment of randomized clinical trials. The search methodology yielded three randomized, placebo-controlled trials, seven observational studies and nine case studies/reports. In aggregate, the data available reveal ketamine as a promising treatment for CRPS. The optimum dose, route and timing of administration remain to be determined. Randomized controlled trials are needed to establish the efficacy and safety of ketamine and to determine its long-term benefit in CRPS.

Neurogenic neuroinflammation in fibromyalgia and complex regional pain syndrome

“…135 Drugs such as ketamine that target Nmethyldaspartate receptors (which are present in activated microglia, as well as in dorsal horn transmission neurons) might also downregulate symptoms due to neuroinflammation in patients with fibromyalgia or CRPS, but no adequate trial evidence exists to support this approach. 136,137 Other drugs that target glutamate within the brain and spinal cord, such as memantine, might also downregulate neurogenic inflammation in fibromyalgia and CRPS. 19,138 Conclusions Neurogenic neuroinflammation is a key pathophysio logical mechanism in both fibromyalgia and CRPS.…”

Intrinsic brain networks normalize with treatment in pediatric complex regional pain syndrome

“…We suggest that a reversal of brain network alterations to a normative state might be indicative of an individual's brain ability to recover. While this is more likely in children, having imaging measures that define recovery (Maihöfner et al, 2004; Becerra et al, 2009) may be used to identify potential responders and non-responders in the more treatment-resistant adult CRPS population (Azari et al, 2012). …”

Ketamine for Post-Operative Analgesia in Paediatrics

“…The influence of the administrated ketamine on pain and sedation was separately analyzed through a grading scale after leaving the operation room. The evaluation was usually reported by the physician, with the smallest number being reported as no complaint or alert state, and the greatest number being reported as the severe complaint imaginable or asleep with no response to physical stimuli [17].…”