A Phase IV Randomized Trial of Maxigesic® Versus Standard Analgesia After Radical Gastrectomy

Background: Radical gastrectomy causes moderate-to-severe pain during the first 48 hours after surgery. Opioids are effective but carry adverse effects and risks of prolonged use, so ERAS-based care recommends multimodal analgesia. Acetaminophen is the most commonly used non-opioid analgesic in gastrectomy patients; adding ibuprofen as a fixed-dose combination has shown improved analgesia and opioid-sparing effects compared with acetaminophen alone in other surgical populations, but direct evidence in gastrectomy patients is limited.

Objective: To evaluate whether scheduled administration of an acetaminophen-ibuprofen fixed-dose combination (Maxigesic® IV) is superior to acetaminophen alone for pain relief after radical gastrectomy, with exploratory assessment of cost-effectiveness and of differences in analgesic efficacy according to genetic polymorphisms.

Hypothesis: When given on an identical scheduled regimen, the acetaminophen-ibuprofen fixed-dose combination produces significantly lower pain scores (NRS) over the first 48 postoperative hours than acetaminophen alone (superiority).

Study plan: This is a phase IV, multicenter, double-blind, randomized controlled trial in which 160 gastric cancer patients scheduled for minimally invasive radical gastrectomy (80 per arm) are randomized 1:1 with stratification by institution. In both arms, the assigned drug is given as a 15-minute intravenous infusion every 6 hours, starting 30 minutes before the end of surgery through 48 hours postoperatively. The primary endpoint is the between-group difference in the time-weighted average (TWA) of repeatedly measured resting and active NRS over 48 hours, analyzed using a mixed model for repeated measures (MMRM); secondary endpoints include opioid consumption (MME), the Quality of Recovery score (QoR-15K), the incidence of chronic postsurgical pain (CPSP), and in-hospital costs.