Ondansetron (Zofran) Dosing in Neonates
The recommended dose of ondansetron (Zofran) for neonates is 0.04 mg/kg intravenously or 0.07 mg/kg orally. 1
Dosing Considerations for Neonates
Ondansetron dosing in neonates requires special consideration due to their unique pharmacokinetics and potential for adverse effects:
- IV administration: 0.04 mg/kg per dose 1
- Oral administration: 0.07 mg/kg per dose 1
- Pharmacokinetics: Neonates have a longer elimination half-life compared to adults or older children 1
Clinical Context and Administration Guidelines
When administering ondansetron to neonates, consider the following:
- Ondansetron is not routinely recommended as part of initial resuscitative efforts in the delivery room for newborns with respiratory depression 2
- For neonates with food protein-induced enterocolitis syndrome (FPIES), ondansetron is generally not recommended for those under 6 months of age 2
- For neonates ≥6 months with FPIES:
- Mild symptoms: Consider ondansetron 0.15 mg/kg/dose IM (maximum 16 mg/dose)
- Moderate-severe symptoms: Administer ondansetron 0.15 mg/kg/dose IV or IM (maximum 16 mg/dose) 2
Safety Considerations
Ondansetron should be used with caution in neonates due to potential risks:
- Overdose can cause serious adverse effects including obtundation, seizures, hepatotoxicity, QTc prolongation, and serotonin syndrome 3
- Administer IV doses slowly to minimize the risk of hypotension
- Monitor for:
- Cardiovascular effects (QT prolongation)
- Neurological effects (seizures, altered mental status)
- Hepatic function
Alternative Antiemetics for Neonates
When considering antiemetic therapy in neonates, alternative options may include:
- For specific conditions like hypercyanotic spells in tetralogy of Fallot, morphine is considered the first-line treatment (IV: 0.1 mg/kg) 2
- Diphenhydramine may be used in infants at 1-2 mg/kg per dose (maximum 50 mg) 4, but is not first-line for nausea and vomiting
Monitoring
When administering ondansetron to neonates:
- Monitor vital signs, particularly heart rate and blood pressure
- Observe for neurological symptoms (lethargy, seizures)
- Consider ECG monitoring for QT prolongation with repeated dosing
- Monitor for adequate hydration status
Ondansetron has been shown to be effective in preventing chemotherapy-induced nausea and vomiting in children 5, but specific neonatal data is limited, requiring careful consideration of risks and benefits in this vulnerable population.