Outpatient intravenous ketamine for the treatment of complex regional pain syndrome: A double-blind placebo controlled studySchwartzman, Robert J.*; Alexander, Guillermo M.; Grothusen, John R.; Paylor, Terry; Reichenberger, Erin; Perreault, MariellePAIN: December 2009 - Volume 147 - Issue 1 - p 107–115 doi: 10.1016/j.pain.2009.08.015 Research papers Abstract Author InformationAuthors Article MetricsMetrics ABSTRACT Complex regional pain syndrome (CRPS) is a severe chronic pain condition that most often develops following trauma. The pathophysiology of CRPS is not known but both clinical and experimental evidence demonstrate the important of the NMDA receptor and glial activation in its induction and maintenance. Ketamine is the most potent clinically available safe NMDA antagonist that has a well established role in the treatment of acute and chronic pain. This randomized double-blind placebo controlled trial was designed to evaluate the effectiveness of intravenous ketamine in the treatment of CRPS. Before treatment, after informed consent was obtained, each subject was randomized into a ketamine or a placebo infusion group. Study subjects were evaluated for at least 2 weeks prior to treatment and for 3 months following treatment. All subjects were infused intravenously with normal saline with or without ketamine for 4 h (25 ml/h) daily for 10 days. The maximum ketamine infusion rate was 0.35 mg/kg/h, not to exceed 25 mg/h over a 4 h period. Subjects in both the ketamine and placebo groups were administered clonidine and versed. This study showed that intravenous ketamine administered in an outpatient setting resulted in statistically significant (p < 0.05) reductions in many pain parameters. It also showed that subjects in our placebo group demonstrated no treatment effect in any parameter. The results of this study warrant a larger randomized placebo controlled trial using higher doses of ketamine and a longer follow-up period. Department of Neurology, Drexel University College of Medicine, Philadelphia, PA 19102, USA1 *Corresponding author. Address: Drexel University College of Medicine, Department of Neurology, 245 North 15th Street, Room 7102, Philadelphia, PA 19102, USA. Tel.: +1 215 762 7090; fax: +1 215 762 3161. E-mail address: Robert.email@example.com 1 URL: http://www.drexelmed.edu/Home/AboutTheCollege/DepartmentsCentersandInstitutes/ClinicalDepts/Neurology.aspx. ARTICLE INFO Article history: Received March 30, 2009 Received in revised form July 16, 2009 Accepted August 18, 2009. © 2009 Lippincott Williams & Wilkins, Inc.