Analgesic Equivalence of NSAIDs and a Weak Opioid in Acute Postoperative Pain: A Randomised Controlled Trial
Abstract
Background: : Non-steroidal anti-inflammatory drugs (NSAIDs) and weak opioids such as tramadol are cornerstones of multimodal analgesia, particularly in settings with limited access to potent opioids. However, cross-class equianalgesic data are scarce. This randomized controlled trial evaluated the analgesic equivalence of tramadol, ketorolac, and diclofenac as premedication in patients undergoing minimally invasive surgery.
Methods:: In this double-blind, parallel-group trial, 30 patients undergoing elective minimally invasive surgery under balanced general anaesthesia were randomised to intravenous tramadol 150 mg, ketorolac 60 mg, or diclofenac 150 mg 45 minutes before skin incision. The sample size was calculated using a one-way ANOVA to detect a large effect size (Cohen's f = 0.4) between the three groups in the primary outcome (NRS pain score at 60 minutes), with α = 0.05 and 80% power, yielding 10 patients per group (30 patients total). Pain intensity was assessed using the Numeric Rating Scale (NRS, 0–10) and Verbal Rating Scale (VRS) at recovery room arrival (T0) and at 30 (T1), 60 (T2), and 90 (T3) minutes thereafter. Secondary outcomes included rescue morphine consumption and safety. Between-group comparisons used Kruskal–Wallis tests.
Results:: All three groups converged to a median NRS of 2 by 60 minutes (T2), with no statistically significant differences in pain scores or rescue morphine requirements at T2 or T3 (p > 0.05). At T0 and T1, NRS scores were higher…
How strong is the evidence?
Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 30 participants or records.
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