Intravenous Ketamine for Cancer Pain: A Single-Center Retrospective Analysis Comparing Fixed-Rate Versus Weight-Based Dosing.
Leslie Siegel, Kyle Quirk, Gary Houchard, Sarah Ehrman, Eric McLaughlin, Omar Hajmousa, Maureen Saphire
Author Information
Leslie Siegel: Department of Pharmacy, The Ohio State University James Comprehensive Cancer Center, Columbus, Ohio, USA. ORCID
Kyle Quirk: Department of Pharmacy, The Ohio State University James Comprehensive Cancer Center, Columbus, Ohio, USA. ORCID
Gary Houchard: Department of Pharmacy, The Ohio State University James Comprehensive Cancer Center, Columbus, Ohio, USA. ORCID
Sarah Ehrman: Department of Internal Medicine, Division of Palliative Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA. ORCID
Eric McLaughlin: Center for Biostatistics, The Ohio State University College of Medicine, Columbus, Ohio, USA. ORCID
Omar Hajmousa: The Ohio State University College of Pharmacy, Columbus, Ohio, USA. ORCID
Maureen Saphire: Department of Pharmacy, The Ohio State University James Comprehensive Cancer Center, Columbus, Ohio, USA. ORCID
Although weak evidence exists to support subanesthetic ketamine for cancer pain treatment, successful use may be hindered in the absence of standardized dosing guidance. We aimed to compare the success rates of intravenous ketamine fixed-rate versus weight-based dosing strategies for cancer pain treatment, and to assess patient characteristics that correlate with treatment success. We conducted a single-center retrospective review including non-critically ill adults with cancer pain who received subanesthetic ketamine for at least 24-h. All patients received fixed-rate ketamine; weight-based doses were retrospectively determined using total body weight. Treatment was considered successful if after reaching the maximum prescribed ketamine dose the patient had a 30% reduction in: baseline pain score, as-needed opioid use, or total morphine equivalent daily dose over a standardized 24-h. Of 105 included patients, 51 (48.6%) successfully responded to ketamine. Responders had lower fixed-rate ketamine doses compared to non-responders (median[IQR] 15���mg/hr[10-15] vs. 15���mg/hr[15-20], ���=���0.043), but no difference in retrospectively calculated weight-based doses (0.201��������0.09���mg/kg/hr vs. 0.209��������0.08���mg/kg/hr, ���=���0.59). Responders had higher daily opioid requirements at baseline compared to non-responders (���=���0.04). Though underpowered, our findings suggest that weight-based ketamine dosing may not convey additional benefit over fixed-rate dosing.
