Abstract
Introduction: tonsillectomy in children is associated with many complications such as severe postoperative pain. The analgesic effect of rectal acetaminophen has been demonstrated in various surgical procedures. The aim of this study was to compare the effect of acetaminophen suppository in children 7 to 15 years before and after tonsillectomy on pain relief.
Materials and Methods: In this clinical trial study, 100 children aged 7 to 15 years who were candidates for tonsillectomy were included in the study. Patients were randomly divided into two equal groups. After induction of anesthesia and intubation and 5 minutes before the start of surgery, group A received 40 mg / kg rectal acetaminophen suppository, and group B received the same dose of rectal acetaminophen suppository after surgery and just before extubation and immediately after discontinuation of anesthetic drugs. Patients were then compared in terms of pain and use of analgesic, 1, 3, 6, 12, and 24 hours after the surgery.
Results: In group A, 56% of patients were female and 44% male, and in group B, 52% were male and 48% female (P = 0.688). The mean age of patients in group A was 9.17 ±2.90 years and in group B was 9.5 ±2.49 years (P = 0.543). The mean pain score in each of 1, 3, 6, 12 and 24 hours was significantly lower in group A than in group B (P <0.05 in all cases). Also, the mean changes in pain 24 hours after surgery were significantly lower in group A than group B (P <0.001). Consumption of both oral (P = 0.041) and intravenous (P = 0.008) analgesics was significantly lower in group A than in group B.
Conclusion: Using rectal acetaminophen before tonsillectomy is a more effective way to reduce pain after tonsillectomy than using it after the surgery, which reduces the need for analgesics in these patients after surgery.

Key words: Adenotonsillectomy, Acetaminophen, Pain, Tonsil, Rectal.