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PCA ketamine-morphine versus PCA morphine as post-operative analgesia in colorectal surgery

J Opioid Manag. 2025 Mar-Apr;21(2):141-148. doi: 10.5055/jom.0888.

ABSTRACT

OBJECTIVE: Ketamine has undergone a recent resurgence of interest as an opioid-sparing agent in pain management. The purpose of this study is to evaluate the effectiveness of patient-controlled analgesia (PCA) ketamine-morphine in comparison to conventional PCA morphine alone as post-operative analgesia in colorectal surgery patients.

DESIGN: Double-blind, randomized, controlled study.

SETTING: This study was conducted at a single, tertiary hospital.

PATIENTS: Sixty patients who underwent elective colorectal surgery were randomly assigned into two groups.

INTERVENTIONS: Group A received PCA ketamine-morphine 0.5:0.5 mg mL-1, while Group B received PCA morphine 1 mg mL-1 as post-operative analgesia.

MAIN OUTCOME MEASURES: Patients’ pain scores, total PCA demands, cumulative morphine consumption, side effects, and their overall satisfaction score were recorded and analyzed.

RESULTS: Overall, there was no significant difference in pain score in both groups, except at 24-hour intervals where Group A had significantly lower mean pain score at rest (1.10 ± 1.37 vs 2.10 ± 1.65, p = 0.017). Total PCA demands were comparable between both groups. Cumulative morphine consumptions however were significantly lower in Group A at all intervals with 24.7 ± 15.2 vs 48.9 ± 30.4 mg (p < 0.001) at 24-hour interval and 38.3 ± 22.4 vs 77.8 ± 46.3 mg (p = 0.001) at 48-hour interval. There was no significant difference in the incidence of side effects and overall satisfaction score in both groups.

CONCLUSIONS: PCA ketamine-morphine was as effective as PCA morphine as post-operative analgesia in colorectal surgery, with comparable pain scores, PCA demands, side effects, and significant reduction in morphine consumption.

PMID:40326726 | DOI:10.5055/jom.0888