Comparison of the Effects of Preemptive Intravenous and Rectal Acetaminophen on Pain Management after Inguinal Herniorrhaphy in Children: a Placebo-controlled Study.

BACKGROUND Postoperative pain management is a critical concern in pediatric surgery. Acetaminophen is the safest and most widely used analgesic in children. The present study compared the analgesic efficacy of intravenous (IV) and rectal acetaminophen versus placebo in children undergoing inguinal herniorrhaphy. METHODS A total of 120 children, who were candidate for elective surgical repair of unilateral inguinal hernia, were enrolled and randomly allocated to four groups of 30 patients each to receive IV acetaminophen, acetaminophen suppository, IV placebo, and placebo suppository during surgery. Postoperative pain scores, measured on the Face, Legs, Activity, Cry, and Consolability (FLACC) scale, were recorded and compared. RESULTS The four groups had no significant differences in the mean age, weight, length of stay in the recovery room, and duration of operation. The frequency of postoperative vomiting was significantly lower in the IV and rectal acetaminophen groups compared to the two placebo groups (P = 0.04). The mean pain scores of the two acetaminophen groups were similar during the first two hours after surgery. These scores were significantly lower than the scores of the placebo groups. However, the four groups were not significantly different in terms of pain scores at the fourth, sixth, and 12th postoperative hours. During the first hour after surgery, IV acetaminophen had the largest analgesic effect. Moreover, among all four groups, the IV acetaminophen group had the highest sedation level in the recovery room. CONCLUSION Both IV and rectal acetaminophen were more effective than placebo in pain relief after inguinal hernia repair in children. They were also associated with lower frequencies of postoperative vomiting. The greatest analgesic efficacy of both forms was observed during the first two hours after surgery.