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 (pinteraction<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, 1.12–3.81). Conclusion Our findings suggest that ketamine can effectively reduce refractory cancer pain in stage IV cancer patients.

Keywords

• adverse effects
• cancer pain
• ketamine
• palliative care