Effect of intravenous low-dose S-ketamine on pain in patients with Complex Regional Pain Syndrome: A retrospective cohort study.

In a group of patients with CRPS with refractory pain, low-dose intravenous S-ketamine treatment resulted in effective pain relief during infusion. Although a significant proportion of initial responders became nonresponders at follow-up, half of the patients were still a responder at ~ 4 weeks postinfusion. Further research is needed to investigate mechanisms responsible for pain relief by S-ketamine infusions and to ascertain possible predictors of response to the treatment.