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NCT Number: NCT07500454

Analgesic Equivalence of NSAIDs and Tramadol in Acute Postoperative Pain Following Minimally Invasive Surgery

This pilot randomised controlled trial compared the analgesic equivalence of three intravenous premedication regimens - tramadol 150 mg, ketorolac 60 mg, and diclofenac 150 mg - in adult patients undergoing elective minimally invasive surgery under balanced general anaesthesia. The primary outcome was postoperative pain intensity measured using the Numerical Rating Scale (NRS 0-10) at recovery room arrival and at 30, 60, and 90 minutes thereafter.

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Key information

Conditions

Postoperative Pain Acute Pain Neurologic Manifestations Pain Pain, Postoperative Pathologic Processes Pathological Conditions, Signs and Symptoms Postoperative Complications Signs and Symptoms

Age range

18 year–55 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Hospital Regional "General Ignacio Zaragoza," ISSSTE

Mexico City, 09360, Mexico

About this study

Acute postoperative pain remains inadequately managed in a substantial proportion of surgical patients, with particular challenges in resource-limited settings where access to potent opioids is restricted. Cross-class equianalgesic data comparing NSAIDs with weak opioids are scarce. This single-centre, double-blind, parallel-group pilot RCT was conducted at Hospital Regional "General Ignacio Zaragoza," ISSSTE, Mexico City. Thirty adult patients (ASA I-II, age 18-55 years, BMI 18.5-34.99 kg/m²) scheduled for elective laparoscopic surgery were randomised equally to receive tramadol 150 mg IV, ketorolac 60 mg IV, or diclofenac 150 mg IV, administered 45 minutes before skin incision. All patients received standardised balanced general anaesthesia. Pain was assessed using the NRS and Verbal Rating Scale (VRS) at five time points. Rescue analgesia (morphine 3 mg IV) was available on request. The trial was initially registered with the ISSSTE institutional research registry (RPI #403-2024).

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age 18-55 years
  • ASA physical status I or II
  • Body mass index 18.5-34.99 kg/m²
  • Scheduled for elective minimally invasive surgery under balanced general anaesthesia
  • Pre-surgical pain NRS = 0 and VRS = "absence" at baseline assessment

Exclusion criteria

  • Pregnancy
  • Known hypersensitivity to any study drug (tramadol, ketorolac, or diclofenac)
  • Pre-existing acute pain with NRS ≥ 4 or VRS ≥ "moderate" before surgery
  • Chronic pain with current analgesic use
  • Withdrawal of consent before premedication administration
  • Surgical duration exceeding 180 minutes
  • Conversion from laparoscopic to open surgical approach
  • Hypersensitivity reaction during study drug administration
  • Haemodynamic shock of any aetiology during the perioperative period
  • Requirement for postoperative mechanical ventilation due to anaesthetic-surgical complications

Treatment and study plan

Tramadol

Drug

Tramadol 150 mg IV, single dose, administered in 100 mL 0.9% saline 45 minutes before skin incision.

Ketorolac

Drug

Ketorolac 60 mg IV, single dose, administered in 100 mL 0.9% saline 45 minutes before skin incision.

Diclofenac

Drug

Diclofenac 150 mg IV, single dose, administered in 100 mL 0.9% saline 45 minutes before skin incision.

Primary outcomes

  1. Postoperative pain intensity

    Time frame: At recovery room arrival (Time_0), and at 30 (Time_1), 60 (Time_2), and 90 (Time_3) minutes after recovery room arrival.

    Pain intensity assessed using the Numerical Rating Scale (NRS, 0-10; 0 = no pain, 10 = worst imaginable pain). Between-group comparisons performed at each time point using Kruskal-Wallis tests with Dunn post-hoc correction.

Secondary outcomes

  1. Categorical pain intensity by Verbal Rating Scale (VRS)

    Time frame: At recovery room arrival (Time_0), and at 30 (Time_1), 60 (Time_2), and 90 (Time_3) minutes after recovery room arrival.

    Pain category assessed using a four-point Verbal Rating Scale (0 = absence, 1 = low, 2 = moderate, 3 = severe). Between-group differences assessed using Pearson's chi-squared test with Cramér's V as effect size.

  2. Rescue morphine consumption

    Time frame: At 30 (Time_1), 60 (Time_2), and 90 (Time_3) minutes after recovery room arrival.

    Number of rescue analgesic doses and total morphine consumed (mg IV) per group. Rescue analgesia (morphine 3 mg IV) was administered on patient request or clinical indication.

  3. Incidence of hypersensitivity reactions

    Time frame: Throughout the 90-minute observation period

    Hypersensitivity reactions of any grade classified according to Müller criteria (Grade I-IV). Managed per institutional protocol (hydrocortisone 100 mg IV; adrenaline 0.5 mg IM for anaphylaxis).

Sponsors and collaborators

Lead sponsor

ISSSTE Hospital Regional "Gral. Ignacio Zaragoza"

Other Gov

Registry information

Official study title

Analgesic Equivalence of NSAIDs and a Weak Opioid in Acute Postoperative Pain Following Minimally Invasive Surgery Under Balanced General Anaesthesia: A Pilot Randomised Controlled Trial

Important dates

Study start
2024
Primary completion
2024
Study completion
2024
First posted
Mar 30, 2026
Registry last updated
Jul 10, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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