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

July 9, 2026 updated by: Mirna Magali Delgado Carlo, ISSSTE Hospital Regional "Gral. Ignacio Zaragoza"

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

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.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

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).

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
30

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Mexico
    • Mexico City
      • Mexico City, Mexico City, Mexico, 09360
        • Hospital Regional "General Ignacio Zaragoza," ISSSTE

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: TRAM
Participants received tramadol 150 mg IV in 100 mL 0.9% saline, administered 45 minutes before skin incision as a single premedication dose, under double-blind conditions.
Drug: Tramadol
Tramadol 150 mg IV, single dose, administered in 100 mL 0.9% saline 45 minutes before skin incision.
Active Comparator: KETO
Participants received ketorolac 60 mg IV in 100 mL 0.9% saline, administered 45 minutes before skin incision as a single premedication dose, under double-blind conditions.
Drug: Ketorolac
Ketorolac 60 mg IV, single dose, administered in 100 mL 0.9% saline 45 minutes before skin incision.
Active Comparator: DICLO
Participants received diclofenac 150 mg IV in 100 mL 0.9% saline, administered 45 minutes before skin incision as a single premedication dose, under double-blind conditions.
Drug: Diclofenac
Diclofenac 150 mg IV, single dose, administered in 100 mL 0.9% saline 45 minutes before skin incision.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
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.
At recovery room arrival (Time_0), and at 30 (Time_1), 60 (Time_2), and 90 (Time_3) minutes after recovery room arrival.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
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.
At recovery room arrival (Time_0), and at 30 (Time_1), 60 (Time_2), and 90 (Time_3) minutes after recovery room arrival.
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.
At 30 (Time_1), 60 (Time_2), and 90 (Time_3) minutes after recovery room arrival.
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).
Throughout the 90-minute observation period

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
ISSSTE Hospital Regional "Gral. Ignacio Zaragoza"

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 20, 2024

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
July 23, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 26, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 20, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 25, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 30, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 10, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 9, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • ISSSTE RPI #403-2024

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data underlying the results reported in this article, along with the full analysis code, will be made available following article publication via the corresponding author's public GitHub repository (https://github.com/phabel-LD).

IPD Sharing Time Frame

Beginning at the time of article publication, with no end date.

IPD Sharing Access Criteria

Data and code will be publicly available with no access restrictions via GitHub.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • ANALYTIC_CODE
  • CSR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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