Opioid-Sparing Effects Comparable Between Oral and IV Acetaminophen After Pediatric Tonsillectomy, Adenoidectomy

child in hospital
Mother hand holding child hand who have IV solution in the hospital with love and care
Researchers compared opioid-sparing effects between intravenous acetaminophen and oral acetaminophen in pediatric patients undergoing tonsillectomy and adenoidectomy.

Opioid-sparing effects were comparable between oral and intravenous (IV) acetaminophen loading dose among pediatric patients undergoing tonsillectomy and adenoidectomy, according to findings from a double-blind prospective study published in Pediatric Anesthesiology.

Patients (N=66) undergoing tonsillectomy or adenoidectomy for the treatment of obstructive sleep apnea were enrolled at the University of California Davis Children’s Hospital between 2017 and 2019. Patients were randomly assigned 1:1 to receive 30 mg/kg oral acetaminophen liquid (n=30) or 15 mg/kg IV acetaminophen (n=36) 30 to 60 minutes prior to surgery. All participants also received a placebo for the other administration method to maintain blinding. Total opioid consumption during 24 hours after surgery was assessed.

Patients in the oral and IV cohorts had a mean age of 5.5±2.8 and 6.2±3.0 years; 50.0% and 38.9% were girls; average weight was 24.1±14.5 and 25.3±12.2 kg; and an additional myringotomy/tube procedure was performed among 16.7% and 13.9%, respectively.

At 24 hours, there was no significant difference in opioid use (median difference, 21.3; 95% CI, -2.5 to 44.2; P =.13). No group differences were observed in the percentage of patients reporting severe pain overall (relative risk [RR], 0.94; 95% CI, 0.57-1.6; P =.82) and after leaving the postanesthesia care unit (RR, 0.83; 95% CI, 0.12-5.6; P =.85).

Recipients of the oral vs IV acetaminophen loading dose received more fentanyl doses (median, 2 vs 1 dose; P =.048).

Acetaminophen plasma levels at the end of surgery tended to be greater in the oral vs IV acetaminophen group (median, 22 vs 20 mg/L; P =.06) and were significantly higher 3 hours after administration (median, 18 vs 11 mg/L; P =.0001).

The study may have been confounded, as the researchers did not adjust for multiple testing.

These findings suggested that oral or IV acetaminophen loading dose prior to surgery did not affect 24-hour opioid consumption among a pediatric population. The researchers also highlighted that oral medications could be a cost-saving approach to adequate surgical pain management.


Lammers CR, Schwinghammer AJ, Hall B, et al. Comparison of oral loading dose to intravenous acetaminophen in children for analgesia after tonsillectomy and adenoidectomy: a randomized clinical trial. Anesth Analg. 2021;133(6):1568-1576. doi:10.1213/ANE.0000000000005678