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Subdissociative Dose Ketamine Is Effective for Treating Acute Exacerbations of Chronic Pain.
Acad Emerg Med. 2019 Mar 22;:
Authors: Lumanauw DD, Youn S, Horeczko T, Yadav K, Tanen DA
Abstract
BACKGROUND: Sub-dissociative dose ketamine (SDDK) is used to treat acute pain. We sought to determine if SDDK is effective in relieving acute exacerbations of chronic pain.
METHODS: Randomized double-blind placebo-controlled trial conducted May 2017-June 2018 at a public teaching hospital (ClinicalTrials. gov#NCT02920528). Primary endpoint was a 20 mm decrease on a 100 mm Visual Analog Scale (VAS) at 60 minutes. Power analysis using three groups (ketamine 0.5 mg/kg, 0.25 mg/kg, or placebo infused over 20 minutes) estimated 96 subjects were needed for 90% power. Inclusion: age >18 years, chronic pain >3 months, acute exacerbation (VAS ≥70 mm). Pain, agitation, and sedation were assessed by VAS at baseline and 20, 40, 60 min after initiation of study drug. Telephone follow-up at 24-48 hr used a 10-point Likert pain scale.
RESULTS: 106 subjects were recruited, 3 excluded for baseline pain <70mm. After randomization, 35 received 0.5 mg/kg, 36 received 0.25 mg/kg, and 35 received placebo. Three subjects receiving 0.5 mg/kg withdrew during the infusion due to adverse effects, and 1 subject in each group had incomplete data, leaving 97 for analysis. Initial pain scores (91.9 ±8.9 mm), age (46.5±12.6 years), gender distribution and types of pain reported were similar. Primary endpoint analysis found 25/30 (83%) improved with 0.5 mg/kg, 28/35 (80%) with 0.25 mg/kg, and 13/32 (41%) with placebo (p=0.001). More adverse effects occurred in the ketamine groups with one subject in the 0.25 mg/kg group requiring a restraint code for agitation. 89% of subjects were contacted at 24-48 hr and no difference in pain level was detected between groups.
CONCLUSION: Ketamine infusions at both 0.5 mg/kg and 0.25 mg/kg over 20 minutes were effective in treating acute exacerbations of chronic pain but resulted in more adverse effects compared to placebo. Ketamine did not demonstrate longer term pain control over the next 24-48 hr. This article is protected by copyright. All rights reserved.
PMID: 30901130 [PubMed - as supplied by publisher]