Ondansetron vs. Dexamethasone for Postoperative Nausea

Phase 4

Recruiting

• Conditions: Postoperative Nausea and Vomiting (PONV)
• Interventions: Drug: Placebo (Normal Saline); Drug: Ondansetron (Zofran); Drug: Dexamethasone

• Registration Number: NCT06886230
• Lead Sponsor: Hafiz Muhammad Hamza

Brief Summary

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.

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 Timeline

• Status Verified: 2025-03
• Study First Submitted: 2025-03-06
• Study First Submitted QC: 2025-03-13
• Study Start: 2025-03-20
• Study First Posted: 2025-03-20
• Last Update Submitted: 2025-05-04
• Last Update Posted: 2025-05-07
• Primary Completion: 2025-07-15
• Study Completion: 2025-08

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 120

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 & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Arm 1: Placebo Group (Control)	Placebo (Normal Saline)	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.
Arm 2: Ondansetron Group	Ondansetron (Zofran)	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.
Arm 3: Dexamethasone Group	Dexamethasone	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.
Arm: 4 Combination Therapy Group	Ondansetron (Zofran)	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.
Arm: 4 Combination Therapy Group	Dexamethasone	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.

Primary Outcome Measures

Name	Time	Method
Incidence of Postoperative Nausea and Vomiting (PONV)	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.

Secondary Outcome Measures

Name	Time	Method
Severity of Postoperative Nausea and Vomiting (Postoperative Nausea and Vomiting Impact Scale Score)	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.
Postoperative Pain Scores (Visual Analog Scale Score)	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.
Need for Rescue Medication	24 hours	Frequency and timing of rescue antiemetic administration in both groups. Determines the effectiveness of the interventions in controlling postoperative nausea and vomiting.
Adverse Effects of Medications	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.
Satisfaction with Postoperative Nausea and Vomiting Management	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.
Apfel Score: Risk Assessment for Postoperative Nausea and Vomiting (PONV)	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.
Heart Rate	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.
Blood Pressure	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.
Respiratory Rate	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.
Oxygen Saturation	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.

Trial Locations

Locations (1)

Federal Government Polyclinic (Postgraduate Medical Institute); 🇵🇰 Islamabad, Capital, Pakistan