The effects of ketamine on pain control in stage IV cancer patients receiving palliative care

Abstract

Background: We evaluated the effects of intravenous ketamine on cancer pain in stage IV cancer patients receiving palliative care.Methods: In total, 253 stage IV cancer patients with cancer pain hospitalized at a single tertiary hospital palliative care unit were included. The ketamine group contained 112 patients receiving ketamine, and the control group comprised 141 non-ketamine users. To evaluate the odds ratios (ORs) for favorable pain control, optimal pain control, and opioid-sparing effect among ketamine users, we used multivariable logistic regression adjusted for age and objective prognosis score. Differences in the visual analog scale (VAS) score, oral morphine equivalents, inter-dose frequency, and inter-dose amount were compared between both groups at the time of ketamine introduction (T0), after 24 hours (T1), and after 48 hours (T2) using repeated-measures analysis of covariance.Results: The ketamine group was more likely to show favorable pain control (OR, 3.84; 95% confidence interval [CI], 1.76–8.37) and an optimal response (OR, 3.99; 95% CI, 1.73–9.22) than the control group. Compared to the control group, the ketamine group showed a higher VAS score at T0, but a more evident VAS score reduction at T1 and T2 (pint<0.001). The ketamine group was less likely than the control group to experience depressive mood (OR, 0.31; 95% CI, 0.10–0.92), but had a higher risk of delirium (OR, 2.06; 95% CI, 1.12–3.91).Conclusion: Our findings suggest that ketamine can effectively reduce refractory cancer pain in stage IV cancer patients.