Seeking a viable perioperative preemptive analgesia regimen: a prospective, randomized, controlled, double-blind superiority study of intravenous acetaminophen in children undergoing adenotonsillectomy.

Objective: To evaluate the analgesic efficacy and safety of pre-induction intravenous acetaminophen in preschool children undergoing day-case adenotonsillectomy. Methods: A prospective, randomized, double-blind, placebo-controlled trial was conducted in 80 children aged 3-6 years. Participants received 15 mg/kg intravenous acetaminophen or saline 15 min prior to anesthetic induction. The primary outcome was FLACC pain score at 1 h post-extubation. Secondary outcomes included FLACC scores at other postoperative time points, PAED emergence delirium scores, PACU opioid rescue rates, home analgesia use, and adverse events within 24 h. Results: At 1 h post-extubation, FLACC scores were significantly lower in the acetaminophen group [median difference -1.0, 95% CI -2.0 to -1.0; Conclusions: Pre-induction intravenous acetaminophen effectively reduces early postoperative pain and PACU opioid requirements without increasing adverse events in preschool children undergoing day-case adenotonsillectomy. Emergence delirium was unaffected in this low-risk population. The findings support its use as a foundational component of multimodal analgesia strategies in pediatric day-case adenotonsillectomy. Clinical Trial Registration: https://www.chictr.org.cn/showproj.html?proj=213700, ChiCTR2400079538.