Comparison of Analgesic Effects of Intravenous or Rectal Acetaminophen for Controlling Post-Tonsillectomy Pain

Background: Acetaminophen is a simple analgesic and antipyretic administered in varied formats and from different routes. The purpose of this study was to compare the efficacy of intravenous (IV) and rectal acetaminophen (RA) for controlling post-tonsillectomy pain. Methods: In a double-blinded randomized clinical trial, 70 children scheduled for adenotonsillectomy were randomly allocated into two groups, each containing 35 patients.In the first group, 40 mg/kg of rectal acetaminophen and in the second group, 15 mg/kg of IV acetaminophen was administered at the end of surgery before extubation. Systolic and diastolic blood pressure and heart rate were measured every 15 minutes after intubation. Face pain score was recorded for every 30 minutes between extubation and discharge from recovery room. The data from both groups were analyzed using SPSS program. Results: All demographic findings (age, gender and weight), the size of used endotracheal tubes, initial heart rate, systolic and diastolic blood pressure were comparable in both groups.The pain intensity was reduced in both groups. But this decrease was more prominent in the group who received IV acetaminophen (P=0.006). The changes in systolic blood pressure were not significant in both groups, as well as the changes in systolic blood pressure in recovery room and the ward. Diastolic blood pressure increased both in the recovery room and the ward. The changes were not significant in the ward; whereas, the changes in diastolic blood pressure in recovery room were statistically significant (P=0.008). Heart rate decreased significantly both in the recovery room (P=0.001) and in the ward (P=0.002). Conclusion: Intravenous acetaminophen is more effective than rectal acetaminophen for attenuating post adenotonsillectomy pain in children