• Logo
  • SBMUJournals

Intravenous Acetaminophen Effect on Postoperative Narcotic Analgesic Demand after Elective Cesarean Section

Mahshid Ghasemi, Maryam Vosoughian, Mastaneh Dahi-Taleghani, Mehrnaz Sohrabi, Seyed Amir Mohajerani




Background: Opioid analgesics are the mainstay of the treatment of postoperative pain. Appropriate monitoring of patients receiving opioid analgesics is essential to detect those with side effects such as respiratory depression. The discovery of Acetaminophen as a COX-3 variant may represent a primary central mechanism by which acetaminophen decrease pain. The aim of this study was to assess the effect of intravenous acetaminophen on morphine requirement in post-operation pain after elective cesarean section.

Materials and Methods: In a randomized clinical trial, patients’ candidate for elective cesarean section. In experiment group, intravenous acetaminophen (1000 mg/6 hour) was administered and normal saline to control group. Visual analogue scale (VAS) was measured at 1, 3, 6, 12, and 24 hours post-operation. Besides, Morphine dose requirement were measured during next 24 hours.

Results: 83 patients were enrolled in the study; which 44 patients assigned in placebo group and 39 in Acetaminophen. Mean Age of placebo group was 29.64±5.55 and Acetaminophen was 30.33±5.50 which was not significantly different (p=0.568). Only at 1 and 3 hours, there was a significant difference between two groups of study. Total dose of morphine requirement was 5.73±2.78 mg/24 h in placebo group and 3.64±2.42 in Acetaminophen group which was significantly different (p=0.001).

Conclusion: Intravenous Acetaminophen could decrease post cesarean pain and decrease post operation total morphine requirement particularly at first 3 hours post operation.




Kehlet H, Holte K. Effect of postoperative analgesia on surgical outcome. Br J Anaesth. 2001;87(1):62-72.

Stein C. The control of pain in peripheral tissue by opioids. N Engl J Med. 1995;332:1685.

Kis B, Snipes JA, Busija DW. Acetaminophen and the cyclooxygenase-3 puzzle: Sorting out facts, fictions, and uncertainties. J Pharmacol Exp Ther. 2005;315:1.

Saurabh S, Smith JK, Pedersen M, Jose P, Nau P, Samuel I. Scheduled intravenous acetaminophen reduces postoperative narcotic analgesic demand and requirement after laparoscopic Roux-en-Y gastric bypass. Surg Obes Relat Dis. 2014 Sep 30. pii: S1550-7289(14)00357-8.

Elia N, Lysakowski C, Tramèr MR. Does multimodal analgesia with acetaminophen, nonsteroidal antiinflammatory drugs, or selective cyclooxygenase-2 inhibitors and patient-controlled analgesia morphine offer advantages over morphine alone? Meta-analyses of randomized trials. Anesthesiology. 2005;103(6):1296-304.

Angle PJ, Halpern SH, Leighton BL, Szalai JP, Gnanendran K, Kronberg JE. A randomized controlled trial examining the effect of naproxen on analgesia during the second day after cesarean delivery. Anesth Analg. 2002;95(3):741-5.

Herring BO, Ader S, Maldonado A, Hawkins C, Kearson M, Camejo M. Impact of intravenous acetaminophen on reducing opioid use after hysterectomy. Pharmacotherapy. 2014;34 Suppl 1:27S-33S.

Kelly JS1, Opsha Y, Costello J, Schiller D, Hola ET. Opioid use in knee arthroplasty after receiving intravenous acetaminophen. Pharmacotherapy. 2014;34 Suppl 1:22S-6S. doi: 10.1002/phar.1518.

Ayatollahi V, Faghihi S, Behdad S, Heiranizadeh N, Baghianimoghadam B. Effect of preoperative administration of intravenous paracetamol during cesarean surgery on hemodynamic variables relative to intubation, postoperative pain and neonatal apgar. Acta Clin Croat. 2014;53(3):272-8.

Kvalsvik O, Borchgrevink PC, Hagen L, Dale O. Randomized, double-blind, placebo-controlled study of the effect of rectal paracetamol on morphine consumption after abdominal hysterectomy. Acta Anaesthesiol Scand. 2003;47(4):451-6.

Bjune K, Stubhaug A, Dodgson MS, Breivik H.Additive analgesic effect of codeine and paracetamol can be detected in strong, but not moderate, pain after Caesarean section. Baseline pain-intensity is a determinant of assay-sensitivity in a postoperative analgesic trial. Acta Anaesthesiol Scand. 1996;40(4):399-407.

Hernández-Palazón J, Tortosa JA, Martínez-Lage JF, Pérez-Flores D.Intravenous administration of propacetamol reduces morphine consumption after spinal fusion surgery. Anesth Analg. 2001;92(6):1473-6.

Remy C, Marret E, Bonnet F. Effects of acetaminophen on morphine side-effects and consumption after major surgery: meta-analysis of randomized controlledtrials. Br J Anaesth. 2005;94(4):505-13.

McDaid C, Maund E, Rice S, Wright K, Jenkins B, Woolacott N. Paracetamol andselective and non-selective non-steroidal anti-inflammatory drugs (NSAIDs) forthe reduction of morphine-related side effects after major surgery: a systematic review. Health Technolssess. 2010;14(17):1-153

Ong CK, Seymour RA, Lirk P, Merry AF. Combining paracetamol (acetaminophen) with non-steroidal anti-inflammatory drugs: a qualitative systematic review ofanalgesic efficacy for acute postoperative pain. AnesthAnalg. 2010;110(4):1170-9.

Munishankar B, Fettes P, Moore C, McLeod GA.A double-blind randomised controlled trial of paracetamol, diclofenac or the combination for pain relief after caesarean section. Int J Obstet Anesth. 2008;17(1):9-14.

Remy C, Marret E, Bonnet F.Effects of acetaminophen on morphine side-effects and consumption after major surgery: meta-analysis of randomized controlled trials. Br J Anaesth. 2005;94(4):505-13.

Capdevila X, Barthelet Y, Biboulet P. Effects of perioperative analgesic technique on the surgical outcome and duration of rehabilitation after major knee surgery. Anesthesiology. 1999; 91:8.

DOI: https://doi.org/10.22037/nbm.v4i1.8129