Retrospective Chart Review Evaluating Efficacy and Tolerability of Ketamine Continuous Infusion for Cancer-Related Pain

Abstract

Context

Ketamine is used to treat refractory cancer pain, but evidence for analgesic and opioid-sparing benefits remains mixed.

Objective

This study assessed the efficacy and tolerability of ketamine continuous infusion (CI) for cancer pain.

Methods

This retrospective analysis assessed adult patients admitted to an academic health system between October 2022 and December 2024, who received at least 48 hours of ketamine CI initiated by the palliative team for pain. Data included ketamine dose, morphine equivalent daily dose (MEDD), numerical pain score (NPS), and mean arterial pressure (MAP) throughout ketamine infusion.

Results

34 met the inclusion criteria. Median age was 52.5 years, 53 percent were female, and 79 percent had a solid tumor. Baseline median NPS was 8/10. Ketamine CI was initiated at a median rate of 0.1 mg/kg/hr (mean 0.12, SD 0.04) and titrated to a median maximum of 0.2 mg/kg/hr (mean 0.21, SD 0.10). At 48 hours, the mean paired NPS reduction was 1.4 points (95% CI, 0.5 to 2.4; P = .004). By final infusion day (paired n = 28), the mean reduction was 1.9 points (95 percent CI -2.8 to −1.0; P < .001). MEDD remained stable from baseline (mean 360, SD 371) through the final day (mean 350, SD 356), and MAP was stable across the first 48 hours. No psychoactive adverse effects were identified.

Conclusion

Ketamine CI produced a statistically significant and clinically meaningful reduction in cancer pain that increased over the course of infusion and was tolerated without identified psychoactive or circulatory adverse events.