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
Journal of pain & palliative care pharmacotherapy December 1, 2024 DOI: 10.1080/15360288.2024.2374297 via PubMed
Summary
AI-generated from the abstractAmong 105 adults with cancer pain treated with subanesthetic ketamine, 48.6% responded—achieving a 30% reduction in pain score, as-needed opioid use, or total morphine equivalent daily dose. Responders received lower fixed-rate doses (median 15 mg/hr) than non-responders (median 15–20 mg/hr), but weight-based doses did not differ between groups (0.201 vs. 0.209 mg/kg/hr). Responders had higher baseline opioid needs. The findings suggest weight-based dosing may not improve success over fixed-rate dosing, though the study was underpowered.
Study at a glance
| Characteristics | Retrospective cohort Peer reviewed |
|---|---|
| Sample size | 105 |
| Population | Non-critically ill adults with cancer pain receiving subanesthetic ketamine for at least 24 hours |
| Intervention | Intravenous ketamine |
| Dose | 15 mg/hr (median fixed-rate for responders); 0.201 ± 0.09 mg/kg/hr (mean weight-based for responders) |
| Duration | At least 24 hours of ketamine infusion |
| Topics | Ketamine |
| Keywords | Fixed-rate dose Weight-based dose Pain management Ketamine therapy Cancer treatment |
| Citations | 2 |
| Key finding | Fixed-rate ketamine dosing, but not weight-based dosing, differed between responders and non-responders, suggesting weight-based dosing may not add benefit. |
Abstract
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], p = 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, p = 0.59). Responders had higher daily opioid requirements at baseline compared to non-responders (p = 0.04). Though underpowered, our findings suggest that weight-based ketamine dosing may not convey additional benefit over fixed-rate dosing.