Ondansetron vs. Dexamethasone for Postoperative Nausea

June 12, 2025 updated by: Hafiz Muhammad Hamza

Assessing The Safety and Efficacy of Ondansetron, Dexamethasone, and Their Combined Regimen in Managing Post Operative Nausea and Vomiting: A Randomized Controlled Trial

This randomized controlled trial aims to evaluate the safety and efficacy of Ondansetron, Dexamethasone, and their combination in managing postoperative nausea and vomiting (PONV) in patients undergoing surgery under anesthesia. A total of 100 patients will be randomized into four groups: Placebo, Ondansetron, Dexamethasone, and Ondansetron-Dexamethasone combination. The primary outcome will be the incidence of PONV within 24 hours post-surgery, while secondary outcomes include severity of symptoms, need for rescue medication, adverse effects, and patient satisfaction.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Postoperative nausea and vomiting (PONV) is a common and distressing complication following surgery, affecting patient recovery and satisfaction. This study aims to compare the safety and effectiveness of Ondansetron, Dexamethasone, and their combination for PONV prevention.

The study will be conducted as a randomized, controlled trial at Federal Polyclinic Hospital Islamabad over four months. A total of 100 adult patients undergoing elective surgery under anesthesia will be enrolled and randomly allocated into one of four groups (n=25 each):

Placebo group - Receives no prophylactic antiemetic treatment. Ondansetron group - Receives 4 mg IV Ondansetron before surgery. Dexamethasone group - Receives 8 mg IV Dexamethasone before surgery. Ondansetron-Dexamethasone group - Receives 4 mg IV Ondansetron + 8 mg IV Dexamethasone before surgery.

Methodology:

Patients will be assessed at multiple time points (2, 4, 6, 12, and 24 hours postoperatively) for PONV incidence and severity, along with the need for rescue medication. Side effects such as headache, dizziness, hypertension, and hyperglycemia will also be monitored.

Statistical Analysis:

Data will be analyzed using chi-square tests and ANOVA to compare outcomes across treatment groups. A p-value < 0.05 will be considered statistically significant.

This study will help determine the most effective and safest antiemetic regimen, guiding clinical decision-making for better PONV management.

Study Type

Interventional

Enrollment (Actual)

105

Phase

  • Phase 4

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

  • Pakistan
    • Capital
      • Islamabad, Capital, Pakistan, 051
        • Federal Government Polyclinic (Postgraduate Medical Institute)

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Adult patients (≥18 years) scheduled for elective surgery under anesthesia.
  • Patients at moderate to high risk for postoperative nausea and vomiting (PONV), as determined by an Apfel risk score ≥2.
  • Patients able to provide informed consent or have a legally authorized representative provide consent.

Exclusion Criteria:

  • Known allergy or hypersensitivity to Ondansetron, Dexamethasone, or any of their components.
  • History of significant adverse reactions to previous PONV prophylaxis with Ondansetron or Dexamethasone.
  • Pre-existing conditions or medications contraindicating the use of Ondansetron or Dexamethasone, e.g. QT prolongation or severe cardiac arrhythmias (e.g., torsades de pointes, congenital long QT syndrome), Uncontrolled hypertension (for Dexamethasone use), Severe hepatic impairment (Child-Pugh C) or end-stage renal disease, Uncontrolled diabetes mellitus (due to Dexamethasone-induced hyperglycemia).
  • Patients with active malignancy undergoing chemotherapy or radiotherapy.
  • Pregnant or lactating women (unless safety in this population is specifically being studied).
  • Chronic opioid users (≥3 months of continuous opioid use), as this may alter PONV risk and response to prophylaxis.

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: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Arm 1: Placebo Group (Control)
Patients in this group will receive a placebo (normal saline) intravenously before surgery. This group serves as a control to compare the efficacy and safety of the active treatment regimens.
Drug: Placebo (Normal Saline)
Patients in this group will receive an intravenous (IV) injection of normal saline before surgery. This serves as a control group to compare the efficacy of active treatment groups in preventing postoperative nausea and vomiting.
Other Names:
  • Saline Injection
  • Inert Solution
Active Comparator: Arm 2: Ondansetron Group
Patients in this group will receive a single dose of Ondansetron 4 mg IV before surgery. Ondansetron is a 5-hydroxytryptamine type 3 receptors antagonist commonly used for postoperative nausea and vomiting prevention.
Drug: Ondansetron (Zofran)
Patients in this group will receive a single intravenous (IV) dose of Ondansetron 4 mg before surgery. Ondansetron is a selective 5-HT3 receptor antagonist commonly used to prevent nausea and vomiting associated with anesthesia and surgery.
Other Names:
  • Zofran
  • Ondem
  • Emeset
Active Comparator: Arm 3: Dexamethasone Group
Patients in this group will receive a single dose of Dexamethasone 8 mg IV before surgery. Dexamethasone is a corticosteroid that has been shown to reduce postoperative nausea and vomiting.
Drug: Dexamethasone
Patients in this group will receive a single intravenous (IV) dose of Dexamethasone 8 mg before surgery. Dexamethasone is a corticosteroid with anti-inflammatory properties that has been shown to reduce the incidence of PONV by modulating inflammatory pathways and neuroreceptor activity.
Other Names:
  • Decadron
  • Dexasone
Active Comparator: Arm: 4 Combination Therapy Group
Patients in this group will receive a combination of Ondansetron 4 mg IV and Dexamethasone 8 mg IV before surgery. The combination therapy is expected to have an additive effect in reducing PONV.
Drug: Ondansetron (Zofran)
Patients in this group will receive a single intravenous (IV) dose of Ondansetron 4 mg before surgery. Ondansetron is a selective 5-HT3 receptor antagonist commonly used to prevent nausea and vomiting associated with anesthesia and surgery.
Other Names:
  • Zofran
  • Ondem
  • Emeset
Drug: Dexamethasone
Patients in this group will receive a single intravenous (IV) dose of Dexamethasone 8 mg before surgery. Dexamethasone is a corticosteroid with anti-inflammatory properties that has been shown to reduce the incidence of PONV by modulating inflammatory pathways and neuroreceptor activity.
Other Names:
  • Decadron
  • Dexasone

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of Postoperative Nausea and Vomiting (PONV)
Time Frame: 24 hours

Defined as the presence of nausea and/or vomiting at any assessment time point (recovery, 2, 4, 6, 12, and 24 hours postoperatively).

Comparison of postoperative nausea and vomiting incidence between the Ondansetron-Dexamethasone and Ondansetron groups.

The need for rescue antiemetic administration as an indicator of postoperative nausea and vomiting severity.
24 hours

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Severity of Postoperative Nausea and Vomiting (Postoperative Nausea and Vomiting Impact Scale Score)
Time Frame: 24 hours

Assessment of the frequency, severity, and impact of nausea and vomiting on daily activities and quality of life.

Measured using patient-reported responses to the Postoperative Nausea and Vomiting Impact Scale.

Scoring Range: 0 to 6 Minimum Score (0): No impact of nausea or vomiting Maximum Score (6): Severe impact on daily activities Interpretation: Higher scores indicate a worse outcome, with greater severity and impact of PONV.
24 hours
Postoperative Pain Scores (Visual Analog Scale Score)
Time Frame: 24 hours

Pain intensity recorded at recovery, 2, 6 and 24 hours postoperatively using the Visual Analog Scale. A 10-point scale ranging from 0 (no pain) to 10 (worst possible pain). Higher scores indicate greater pain severity.

Comparison of pain levels between the two groups to determine any analgesic effects of dexamethasone.
24 hours
Need for Rescue Medication
Time Frame: 24 hours
Frequency and timing of rescue antiemetic administration in both groups. Determines the effectiveness of the interventions in controlling postoperative nausea and vomiting.
24 hours
Adverse Effects of Medications
Time Frame: 24 hours

Frequency of ondansetron-related side effects: headache, dizziness, constipation, diarrhea, fatigue, allergic reactions.

Frequency of dexamethasone-related side effects: increased appetite, insomnia, mood changes, fluid retention, hypertension, hyperglycemia.
24 hours
Satisfaction with Postoperative Nausea and Vomiting Management
Time Frame: 24 hours

Patient-reported satisfaction levels with nausea and vomiting management, measured using the satisfaction scale in the questionnaire.

Each response is scored on a 5-point Likert scale, where:

  1. = Very dissatisfied (minimum score)
  2. = Somewhat dissatisfied
  3. = Neutral
  4. = Somewhat satisfied
  5. = Very satisfied (maximum score) The total score ranges from 5 (minimum satisfaction) to 25 (maximum satisfaction), with higher scores indicating better patient satisfaction.
24 hours
Apfel Score: Risk Assessment for Postoperative Nausea and Vomiting (PONV)
Time Frame: 24 hours
Apfel Score Components (Each Risk Factor = 1 Point) Female gender → (Yes = 1 point, No = 0 points) History of postoperative nausea and vomiting or motion sickness → (Yes = 1 point, No = 0 points) Non-smoker → (Yes = 1 point, No = 0 points) Planned use of postoperative opioid analgesia → (Yes = 1 point, No = 0 points) Higher Apfel Scores indicate an increased risk of postoperative nausea and vomiting.
24 hours
Heart Rate
Time Frame: 24 hours
Heart rate (beats per minute) will be continuously monitored and recorded at predefined intraoperative and postoperative time points to assess hemodynamic stability and detect potential bradycardia or tachycardia.
24 hours
Blood Pressure
Time Frame: 24 hours
Systolic and diastolic blood pressure (measured in mmHg) will be recorded at regular intraoperative and postoperative intervals to monitor hemodynamic stability and detect episodes of hypotension or hypertension.
24 hours
Respiratory Rate
Time Frame: 24 hours
Respiratory rate (measured in breaths per minute) will be monitored intraoperatively and postoperatively to evaluate respiratory function and detect potential respiratory depression or distress.
24 hours
Oxygen Saturation
Time Frame: 24 hours
Oxygen saturation levels (SpO₂, measured as a percentage) will be continuously monitored throughout the intraoperative and postoperative periods to assess respiratory function and detect hypoxia.
24 hours

Collaborators and Investigators

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

Sponsor

Hafiz Muhammad Hamza

Collaborators

Federal Government Polyclinic (Postgraduate Medical Institute)

Investigators

  • Principal Investigator: Naveed Ullah Khan, Consultant surgery, HOD, Federal Government Polyclinic (Postgraduate Medical Institute)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

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)

March 20, 2025

Primary Completion (Actual)

June 10, 2025

Study Completion (Actual)

June 11, 2025

Study Registration Dates

First Submitted

March 6, 2025

First Submitted That Met QC Criteria

March 13, 2025

First Posted (Actual)

March 20, 2025

Study Record Updates

Last Update Posted (Actual)

June 17, 2025

Last Update Submitted That Met QC Criteria

June 12, 2025

Last Verified

March 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • FGPC.1/12/2024 E-Committee

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

At this stage, no final decision has been made regarding the sharing of individual participant data (IPD). Data sharing will be considered based on future research needs, ethical guidelines, and institutional policies. Any decision to share IPD will be made in compliance with data protection regulations and patient confidentiality standards.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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