Postoperative pain management is a critical aspect of clinical care, with a significant impact on patient recovery and quality of life. Among the pharmacological options available, Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) and acetaminophen (paracetamol) are widely utilized due to their distinct chemical properties and mechanisms of action. This study aims to evaluate and compare the efficacy of intravenous paracetamol (C₈H₉NO₂) and diclofenac (C₁₄H₁₁Cl₂NO₂) in postoperative analgesia, focusing on their pharmacokinetic profiles, safety, and therapeutic outcomes. A prospective randomized controlled trial was conducted on 100 patients undergoing elective general and gynecological surgeries. The participants were divided into two groups: Group I received intravenous paracetamol, and Group II received intravenous diclofenac. Pain intensity was assessed using the Visual Analog Scale (VAS) at different time intervals (0, 2, 4, 6, 12, and 24 hours postoperatively), alongside monitoring physiological parameters such as heart rate, respiratory rate, blood pressure, oxygen saturation, sedation levels, and the incidence of side effects. The results demonstrated that paracetamol, with its central mechanism of COX enzyme inhibition and favorable pharmacokinetic properties, provided superior analgesic efficacy with reduced side effects compared to diclofenac. Paracetamol exhibited a rapid onset of action (within 8 minutes intravenously), minimal protein binding, and renal excretion, leading to a lower requirement for rescue analgesia. In contrast, diclofenac, a potent NSAID with strong anti- inflammatory properties, was associated with gastrointestinal irritation and potential nephrotoxicity, emphasizing the importance of patient-specific considerations.In conclusion, the administration of intravenous paracetamol 30 minutes prior to surgery completion, followed by 1g every 8 hours, offers a chemically safer and clinically effective alternative to diclofenac for postoperative pain management. These findings support the integration of paracetamol in multimodal analgesia strategies to optimize pain relief while minimizing adverse effects.

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1. Varrassi G, Marinangeli F, Agro F, et al. A double-blinded evaluation of propacetamol versus ketorolac in combination with patient-controlled analgesia morphine: analgesic efficacy and tolerability after gynecologic surgery. Anesth Analg. 1999;88:611–616.
2. Witjes WP, Crul BJ, Vollaard EJ, Joosten HJ, von Egmond J. Application of sublingual buprenorphine in combination with naproxen or paracetamol for postoperative pain relief in cholecystectomy patients: a double-blind study. Acta Anaesthesiol Scand. 1992;36:323–327.
3. Cobby TF, Crighton IM, Kyriakides K, Hobbs GJ. Rectal paracetamol has a significant morphine-sparing effect after hysterectomy. Br J Anaesth. 1999;83:253–256.
4. Munishankar B, Fettes P, Moore C, McLeod GA. A double-blind randomized controlled trial of paracetamol, diclofenac, or the combination for pain relief after cesarean section. Int J Obstet Anesth. 2008;17:9–14.
5. Tuzuner Oncul AM, Yazicioglu D, Alanoglu Z, Demiralp S, Ozturk A, Ucok C. Postoperative analgesia in impacted third molar surgery: the role of preoperative diclofenac sodium, paracetamol, and lornoxicam. Med Princ Pract. 2011;20:470–476.
6. Mulrow CD, Cook DJ, eds. Systematic Reviews: Synthesis of Best Evidence for Health Care Decisions. Philadelphia, PA: American College of Physicians; 1998.
7. Choi P, Halpern S, Malik N, et al. Examining the evidence in anesthesia literature: a critical appraisal of systematic reviews. Anesth Analg. 2001;92:700–709.
8. Cook DJ, Sackett DL, Spitzer WO. Methodological guidelines for systematic reviews of randomized controlled trials in healthcare from the Potsdam consultation on meta-analysis. J Clin Epidemiol. 1995;48:167–171.
9. van Tulder MW, Assendelft WJ, Koes BW, Bouter LM. Method guidelines for systematic reviews in the Cochrane Collaboration Back Review Group for Spinal Disorders. Spine. 1997;22:2323–2330.
10. Jadad AR, Moore A, Carroll D, et al. Assessing the quality of reports of randomized clinical trials: is blinding necessary? Control Clin Trials. 1996;17:1–12

Postoperative pain management is a critical aspect of clinical care, with a significant impact on patient recovery and quality of life. Among the pharmacological options available, Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) and acetaminophen (paracetamol) are widely utilized due to their distinct chemical properties and mechanisms of action. This study aims to evaluate and compare the efficacy of intravenous paracetamol (C₈H₉NO₂) and diclofenac (C₁₄H₁₁Cl₂NO₂) in postoperative analgesia, focusing on their pharmacokinetic profiles, safety, and therapeutic outcomes. A prospective randomized controlled trial was conducted on 100 patients undergoing elective general and gynecological surgeries. The participants were divided into two groups: Group I received intravenous paracetamol, and Group II received intravenous diclofenac. Pain intensity was assessed using the Visual Analog Scale (VAS) at different time intervals (0, 2, 4, 6, 12, and 24 hours postoperatively), alongside monitoring physiological parameters such as heart rate, respiratory rate, blood pressure, oxygen saturation, sedation levels, and the incidence of side effects. The results demonstrated that paracetamol, with its central mechanism of COX enzyme inhibition and favorable pharmacokinetic properties, provided superior analgesic efficacy with reduced side effects compared to diclofenac. Paracetamol exhibited a rapid onset of action (within 8 minutes intravenously), minimal protein binding, and renal excretion, leading to a lower requirement for rescue analgesia. In contrast, diclofenac, a potent NSAID with strong anti- inflammatory properties, was associated with gastrointestinal irritation and potential nephrotoxicity, emphasizing the importance of patient-specific considerations.In conclusion, the administration of intravenous paracetamol 30 minutes prior to surgery completion, followed by 1g every 8 hours, offers a chemically safer and clinically effective alternative to diclofenac for postoperative pain management. These findings support the integration of paracetamol in multimodal analgesia strategies to optimize pain relief while minimizing adverse effects.

🔒 This is a subscription article

Full text is available to subscribers and institutional members. Please choose an option below to access it.

1. Varrassi G, Marinangeli F, Agro F, et al. A double-blinded evaluation of propacetamol versus ketorolac in combination with patient-controlled analgesia morphine: analgesic efficacy and tolerability after gynecologic surgery. Anesth Analg. 1999;88:611–616.
2. Witjes WP, Crul BJ, Vollaard EJ, Joosten HJ, von Egmond J. Application of sublingual buprenorphine in combination with naproxen or paracetamol for postoperative pain relief in cholecystectomy patients: a double-blind study. Acta Anaesthesiol Scand. 1992;36:323–327.
3. Cobby TF, Crighton IM, Kyriakides K, Hobbs GJ. Rectal paracetamol has a significant morphine-sparing effect after hysterectomy. Br J Anaesth. 1999;83:253–256.
4. Munishankar B, Fettes P, Moore C, McLeod GA. A double-blind randomized controlled trial of paracetamol, diclofenac, or the combination for pain relief after cesarean section. Int J Obstet Anesth. 2008;17:9–14.
5. Tuzuner Oncul AM, Yazicioglu D, Alanoglu Z, Demiralp S, Ozturk A, Ucok C. Postoperative analgesia in impacted third molar surgery: the role of preoperative diclofenac sodium, paracetamol, and lornoxicam. Med Princ Pract. 2011;20:470–476.
6. Mulrow CD, Cook DJ, eds. Systematic Reviews: Synthesis of Best Evidence for Health Care Decisions. Philadelphia, PA: American College of Physicians; 1998.
7. Choi P, Halpern S, Malik N, et al. Examining the evidence in anesthesia literature: a critical appraisal of systematic reviews. Anesth Analg. 2001;92:700–709.
8. Cook DJ, Sackett DL, Spitzer WO. Methodological guidelines for systematic reviews of randomized controlled trials in healthcare from the Potsdam consultation on meta-analysis. J Clin Epidemiol. 1995;48:167–171.
9. van Tulder MW, Assendelft WJ, Koes BW, Bouter LM. Method guidelines for systematic reviews in the Cochrane Collaboration Back Review Group for Spinal Disorders. Spine. 1997;22:2323–2330.
10. Jadad AR, Moore A, Carroll D, et al. Assessing the quality of reports of randomized clinical trials: is blinding necessary? Control Clin Trials. 1996;17:1–12