Ondansetron (Zofran) Dosing and Administration for Nausea Management
For managing nausea, ondansetron (Zofran) is recommended at a dose of 8 mg orally or intravenously every 8-12 hours as needed, with oral dissolving tablets being particularly effective for patients who have difficulty swallowing. 1
Dosage Options by Route of Administration
Oral Administration
- Standard dose: 8 mg every 8-12 hours as needed 1
- Oral dissolving tablets (ODT): 8 mg every 12 hours 2
- Particularly useful for patients with difficulty swallowing
- No water required for administration
- Rapidly disperses when placed on the tongue
Intravenous Administration
- Standard dose: 8 mg IV over 15 minutes 3
- For chemotherapy-induced nausea: 0.15 mg/kg (maximum 16 mg per dose) infused over 15 minutes, beginning 30 minutes before chemotherapy and repeated 4 and 8 hours after the first dose 3
- For breakthrough symptoms, IV administration is preferred over oral routes 1
- Dilution in 50 mL of 5% Dextrose or 0.9% Sodium Chloride is required before IV administration 3
Clinical Context-Specific Dosing
For Radiation-Induced Nausea
- Oral ondansetron 8 mg, 2-3 times daily, with or without oral dexamethasone 4
- Adding dexamethasone (4 mg daily) to ondansetron provides modest additional benefit 4
For Chemotherapy-Induced Nausea
- Schedule options (equally effective) 5:
- Option 1: 8 mg IV pre-chemotherapy followed by 8 mg orally every 12 hours
- Option 2: 16 mg IV pre-chemotherapy alone
- Maintenance with oral ondansetron after 24 hours is more effective than placebo in preventing delayed nausea and emesis 5
For Postoperative Nausea
- Adult patients: 4 mg IV as a single dose 3
- Pediatric patients (≥1 month): 0.1 mg/kg IV (maximum 4 mg) 3
Safety Considerations
Cardiac Safety
- Avoid doses exceeding 32 mg IV due to risk of QT interval prolongation 6
- Lower doses used for postoperative nausea prevention are generally considered safe 6
- Monitor patients with pre-existing cardiac conditions more closely
Hepatic Impairment
- For severe hepatic impairment (Child-Pugh score ≥10): Maximum daily dose of 8 mg 3
Efficacy Data
- Mean decrease in nausea score of 4.0 on a 10-point scale when administered by paramedics 7
- IV administration provides greater improvement in nausea scores (mean 4.4) compared to ODT (mean 3.3) 7
- Efficacy is maintained over multiple courses of treatment 5
Administration Pearls
- Diluted solutions are stable for 24 hours at room temperature 3
- Compatible with common IV fluids including 0.9% Sodium Chloride and 5% Dextrose 3
- For patients experiencing breakthrough nausea despite prophylaxis, consider adding an agent from a different drug class rather than increasing ondansetron dose 4
- Preventive administration is more effective than treating established symptoms 1
By following these dosing guidelines, ondansetron can effectively manage nausea across various clinical scenarios while minimizing potential adverse effects.