author/presenter Crimean State Medical University named after S.I.Georgivesky Nawan Shaher, Punjab
Background: Ketamine infusions have gained popularity in the treatment of chronic pain syndromes, including complex regional pain syndrome (CRPS) and fibromyalgia. While initial analgesic effects are often dramatic, some patients report worsening pain after discontinuation — a phenomenon known as rebound hyperalgesia. This case series explores the clinical features and outcomes of patients who experienced post-infusion hyperalgesia.
Purpose/Objectives: The purpose of this study is to investigate the occurrence of rebound hyperalgesia in patients with chronic pain following intravenous ketamine infusions. The objective is to characterize the clinical features, timing, and severity of this response, identify potential contributing factors, and explore strategies that may help mitigate symptoms. By increasing awareness of this underrecognized phenomenon, the study aims to inform safer ketamine use and guide future research on optimizing post-infusion pain management.
Methods: A retrospective chart review was conducted at a multidisciplinary pain clinic from January 2023 to March 2024. Patients who received IV ketamine infusions for chronic pain and reported increased pain within 72 hours of discontinuation were included. Clinical data including diagnosis, dose, infusion duration, pain scores, and treatment response were analyzed.
Results: Out of 38 patients who underwent ketamine infusions, 6 (15.8%) developed clinically significant rebound hyperalgesia. Most had CRPS or neuropathic pain. The average increase in pain score post-infusion was 2.1 points on a 0–10 scale. Symptoms typically resolved within 5–7 days, but required rescue analgesia in four patients. Those who tapered adjunct medications more slowly had milder symptoms.
Conclusions/Implications for future research and/or clinical care: While ketamine remains a promising intervention for chronic pain, rebound hyperalgesia may occur in a subset of patients. Clinicians should be aware of this phenomenon and consider strategies such as slower tapering of adjuvants or transitional therapies. Future prospective studies are needed to define risk factors and prevention strategies.
