Comparing the Efficacy of Intravenous Acetaminophen and Intravenous Meperidine in Pain Relief After Outpatient Urological Surgery

Background: Pain relief after surgery is an essential component of postoperative care. Objectives: The purpose of this study was to compare the efficacy of intravenous acetaminophen and intravenous meperidine in pain relief after outpatient urological surgery. Patients and Methods: In a prospective, randomized, double-blind clinical trial, 100 outpatients of urological surgery were studied in two groups of acetaminophen (A) and meperidine (M). Patients in group A received 1g of acetaminophen in 100 mL saline within 15 minutes and patients in group M received a single intravenous injection of meperidine 0.5 mg/kg, 15 minutes prior to the end of operation. Postoperative pain was recorded using visual analog scale (VAS). Vital signs, nausea, vomiting, dizziness and respiratory depressions were compared between the two groups. Results: Pain severity in patients treated with intravenous acetaminophen six hours after the operation within one-hour interval was significantly lower than meperidine group (P < 0.0001). Ninety patients in the meperidine group and five patients in the acetaminophen group required additional doses of analgesics. Nausea was significantly lower in acetaminophen group than meperidine group. Conclusions: Intravenous acetaminophen reduced pain following outpatient urological surgery more significantly than meperidine.