[Effect of intravenous acetaminophen versus fentanyl on postoperative pain after transurethral lithotripsy]

Braz J Anesthesiol. 2019 Mar-Apr;69(2):131-136. doi: 10.1016/j.bjan.2018.06.009. Epub 2019 Jan 15.
[Article in Portuguese]


Background: Postoperative pain is the most common postoperative complication. This study was conducted to assess the effect of acetaminophen versus fentanyl on postoperative pain relief in patients who underwent urologic surgeries.

Methods: This clinical trial was conducted on patients aged 18–65 years. Patients were randomly assigned to receive either 2000 mg acetaminophen (propacetamol) or 2 mcg.kg−1 fentanyl intravenously, 15 min before the end of surgery. The postoperative pain was evaluated every 6 h for 24 h using the Visual Analog Scale. Total morphine dose taken in 24 h and hemodynamic status were evaluated.

Results: Eighty patients were enrolled into the trial. The mean score of pain in 6, 12, 18, and 24 h after surgery was lower in the acetaminophen group than in the fentanyl group but the difference was not statistically significant except in 12 and 18 h after surgery (p < 0.05). The amount of administered morphine was higher in the fentanyl group than in the acetaminophen group, but the difference was not statistically significant. The hemodynamic status including systolic and diastolic blood pressure and heart rates were nearly the same in the two groups but the SpO2 mean was significantly higher in the acetaminophen group than the fentanyl group.

Conclusions: This trial indicated that intravenous acetaminophen is as effective as intravenous fentanyl in pain relief after urologic surgeries (transurethral lithotripsy).

Keywords: Acetaminofeno; Acetaminophen; Dor pós‐operatória; Fentanil; Fentanyl; Hemodynamic parameters; Litotripsia transuretral; Morfina; Morphine; Parâmetros hemodinâmicos; Postoperative pain; Transurethral lithotripsy.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Acetaminophen / administration & dosage*
  • Administration, Intravenous
  • Adolescent
  • Adult
  • Aged
  • Analgesics, Non-Narcotic / administration & dosage
  • Analgesics, Opioid / administration & dosage
  • Female
  • Fentanyl / administration & dosage*
  • Humans
  • Lithotripsy / methods*
  • Male
  • Middle Aged
  • Pain Measurement
  • Pain, Postoperative / drug therapy*
  • Single-Blind Method
  • Time Factors
  • Young Adult


  • Analgesics, Non-Narcotic
  • Analgesics, Opioid
  • Acetaminophen
  • Fentanyl