Saul Flores

Purpose To evaluate the efficacy, safety, and cost of clonidine compared with fentanyl as an adjuvant for analgesia in patients undergoing inguinal hernia repair. Methods This randomized superiority trial included 138 patients allocated to fentanyl (GLF) or clonidine (GLC) groups (n = 69 each), undergoing inguinal hernioplasty under local anesthesia with sedation. The primary outcome was postoperative pain intensity assessed by the visual analog scale (VAS). Secondary outcomes included time to first analgesic request, need for rescue analgesia, sedation level (RASS), adverse events, and medication costs. Results were expressed as mean or median differences, or relative risks, with 95% CI. Results Baseline characteristics were comparable between groups. Clonidine significantly reduced pain intensity compared with fentanyl (median 0 [IQR 0–3] vs. median 2 [IQR 0–4]; Mann–Whitney U = 1864; 95% CI of median difference − 3.00 to − 2.00; p = 0.019). The clonidine group also showed greater sedation (mean difference − 0.6; p = 0.009), longer pain-free time (mean difference 2.0 h; p = 0.001), and lower need for rescue analgesia (34.8% vs. 59.4%; RR 0.59; p = 0.006). Adverse events and costs were similar. The reduced need for rescue analgesia suggests a clinically relevant opioid-sparing effect. Conclusion Clonidine was superior to fentanyl in improving postoperative analgesia, prolonging pain-free duration, and reducing additional analgesic requirements, while maintaining a comparable safety profile and cost.