What are the dosages of ondansetron (antiemetic medication) and pantoprazole (proton pump inhibitor)?

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Ondansetron and Pantoprazole Dosing

For ondansetron, use 8 mg IV or 16-24 mg PO on day 1 before chemotherapy, followed by 8 mg PO twice daily for 2-3 days afterward; for pantoprazole, the standard dose is 40 mg IV or PO daily.

Ondansetron Dosing

For Chemotherapy-Induced Nausea and Vomiting

High Emetogenic Risk:

  • Day 1: 16-24 mg PO once daily OR 8-12 mg IV (maximum 16 mg per dose due to cardiac safety concerns) given 30 minutes before chemotherapy 1, 2
  • Days 2-3: 8 mg PO twice daily or 16 mg PO once daily 1
  • The FDA-approved regimen is 0.15 mg/kg IV per dose for 3 doses (maximum 16 mg per dose), infused over 15 minutes beginning 30 minutes before chemotherapy, then repeated at 4 and 8 hours after the first dose 2

Moderate Emetogenic Risk:

  • Day 1: 8 mg IV or PO every 8 hours 1, 3
  • Days 2-3: 8 mg PO twice daily 1, 3

Low Emetogenic Risk:

  • 8 mg PO twice daily or 8 mg IV on day of chemotherapy only, with no subsequent day dosing required 3

For Postoperative Nausea and Vomiting

  • Adults: 4 mg IV undiluted over 2-5 minutes immediately before anesthesia induction or postoperatively 2
  • Pediatric patients (1 month to 12 years): Weight-based dosing per FDA label 2
  • Dilution is NOT required for postoperative nausea and vomiting prevention 2

Critical Safety Consideration

The maximum single IV dose is 16 mg due to QT prolongation risk—the FDA has specifically warned against 32 mg IV doses 4. Lower doses appear safer, though QT prolongation has been reported even with standard dosing 4.

Breakthrough Dosing

  • If nausea persists despite scheduled ondansetron, titrate up to a maximum of 16 mg oral or IV daily 3
  • For inpatients with refractory symptoms, 8 mg IV bolus followed by 1 mg/hour continuous infusion may be used 1

Pantoprazole Dosing

Standard Dosing

  • 40 mg IV or PO once daily is the standard dose 5
  • For peptic ulcer disease resistant to H2 blockers, initial doses of 40-80 mg PO daily were used, with most patients healing within 2-8 weeks 6
  • Maintenance therapy: 40 mg daily, though some patients with severe esophagitis required 80-120 mg daily for disease control 6

Administration

  • Available as 40 mg vials for IV reconstitution 5
  • Can be given orally or intravenously depending on patient status 6

Combination Therapy Considerations

When using ondansetron with pantoprazole in the chemotherapy setting, guidelines recommend adding an H2 blocker or proton pump inhibitor (like pantoprazole) to the antiemetic regimen to prevent gastric irritation 1. This combination is particularly important for patients receiving corticosteroids as part of their antiemetic regimen, as steroids increase gastric acid secretion 1.

Common Pitfall

Do not use ondansetron 32 mg IV—this dose is no longer recommended due to cardiac arrhythmia risk 4. The maximum safe single IV dose is 16 mg 2, 4.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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