TY - JOUR
T1 - Effect of intravenous low-dose S-ketamine on pain in patients with Complex Regional Pain Syndrome
T2 - A retrospective cohort study
AU - Mangnus, Thomas J.P.
AU - Dirckx, Maaike
AU - Bharwani, Krishna D.
AU - de Vos, Cecile C.
AU - Frankema, Sander P.G.
AU - Stronks, Dirk L.
AU - Huygen, Frank J.P.M.
N1 - Publisher Copyright:
© 2021 The Authors. Pain Practice published by Wiley Periodicals LLC on behalf of World Institute of Pain
PY - 2021/11
Y1 - 2021/11
N2 - Objective: The objective of this study was to assess the effectiveness of a low-dose intravenous S-ketamine treatment on refractory pain in patients with Complex Regional Pain Syndrome (CRPS). Methods: In this retrospective study, patients with CRPS who received intravenous S-ketamine from March 2010 to April 2019 were included. According to our inpatient protocol, S-ketamine dose was increased until pain reduction was achieved or side effects were observed. Maximum dose was 14 mg/h and treatment duration was 7 days. Primary outcome parameters were pain scores (Numeric Rating Scale) at baseline (T0), end of infusion (T1), and approximately 4 weeks postinfusion (T2). Patients were categorized as responder/nonresponder at T1 and T2. Patients were considered a responder in case there was pain score reduction of greater than or equal to 2 points or if treatment was reported as successful. Results: Forty-eight patients were included. Mean disease duration was 5 years (interquartile range [IQR] = 6 years). Median pain score significantly decreased from 8 (IQR = 2) at T0 to 6 (IQR = 4) at T1 (p < 0.001). At T1, 62% of the patients were responders. At T2, 48% of the patients remained a responder. A significant proportion of the responders at T1 turned into nonresponders at T2 (p = 0.03). Conclusion: 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.
AB - Objective: The objective of this study was to assess the effectiveness of a low-dose intravenous S-ketamine treatment on refractory pain in patients with Complex Regional Pain Syndrome (CRPS). Methods: In this retrospective study, patients with CRPS who received intravenous S-ketamine from March 2010 to April 2019 were included. According to our inpatient protocol, S-ketamine dose was increased until pain reduction was achieved or side effects were observed. Maximum dose was 14 mg/h and treatment duration was 7 days. Primary outcome parameters were pain scores (Numeric Rating Scale) at baseline (T0), end of infusion (T1), and approximately 4 weeks postinfusion (T2). Patients were categorized as responder/nonresponder at T1 and T2. Patients were considered a responder in case there was pain score reduction of greater than or equal to 2 points or if treatment was reported as successful. Results: Forty-eight patients were included. Mean disease duration was 5 years (interquartile range [IQR] = 6 years). Median pain score significantly decreased from 8 (IQR = 2) at T0 to 6 (IQR = 4) at T1 (p < 0.001). At T1, 62% of the patients were responders. At T2, 48% of the patients remained a responder. A significant proportion of the responders at T1 turned into nonresponders at T2 (p = 0.03). Conclusion: 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.
UR - http://www.scopus.com/inward/record.url?scp=85111163819&partnerID=8YFLogxK
U2 - 10.1111/papr.13056
DO - 10.1111/papr.13056
M3 - Article
C2 - 34233070
AN - SCOPUS:85111163819
SN - 1530-7085
VL - 21
SP - 890
EP - 897
JO - Pain Practice
JF - Pain Practice
IS - 8
ER -