What are the recommended medications for pediatric vomiting?

Recommended Medications for Pediatric Vomiting

Ondansetron is the first-line antiemetic for pediatric vomiting across most clinical contexts, with superior efficacy and safety compared to alternatives like metoclopramide or domperidone. 1, 2

Standard Ondansetron Dosing

Weight-based dosing is the recommended approach:

• Intravenous/Intramuscular: 0.15 mg/kg per dose (maximum 16 mg per dose) 1, 2
• Oral: 0.15 mg/kg or 5 mg/m² body surface area 1
• Age-specific oral dosing per FDA:
  • Ages 12-17 years: 8 mg per dose 3
  • Ages 4-11 years: 4 mg per dose 3
• Single dose maximum: 16 mg regardless of route 1, 4

Ondansetron has been studied and used safely in children as young as 6 months of age, though FDA labeling only extends to age 4 years for some indications. 1

Context-Specific Recommendations

Acute Gastroenteritis with Vomiting

Ondansetron facilitates oral rehydration therapy and reduces hospital admissions:

• The Infectious Diseases Society of America recommends ondansetron for children >4 years with acute gastroenteritis and vomiting 1, 2
• The American Academy of Pediatrics supports weight-based dosing for persistent vomiting 1, 2
• Critical caveat: Antiemetic treatment should not replace appropriate fluid and electrolyte therapy, which remains the cornerstone of management 1, 4
• Ondansetron should be used alongside—not instead of—rehydration efforts 2, 4

Research demonstrates ondansetron is more effective than domperidone at 24 hours (96.6% vs 85% cessation of vomiting, p=0.01) and superior to both bromopride and metoclopramide at 6 and 24 hours post-treatment. 5, 6

Chemotherapy-Induced Nausea and Vomiting

Combination therapy is superior to monotherapy:

• High-emetic-risk chemotherapy: Ondansetron + dexamethasone + aprepitant (three-drug regimen) 1, 2, 4
• Moderate-emetic-risk chemotherapy: Ondansetron + dexamethasone 1, 2, 4
• Low-emetic-risk chemotherapy: Ondansetron monotherapy 1, 2, 4

The addition of dexamethasone significantly improves antiemetic efficacy in chemotherapy settings. 1

Food Protein-Induced Enterocolitis Syndrome (FPIES)

Ondansetron serves as adjunctive management for acute FPIES:

• Mild (1-2 episodes, no lethargy): If age ≥6 months, consider ondansetron IM 0.15 mg/kg (max 16 mg) 4
• Moderate (>3 episodes with mild lethargy): If age >6 months, administer ondansetron IM 0.15 mg/kg; consider IV line with normal saline bolus 20 mL/kg 4
• Severe: Requires aggressive fluid resuscitation with isotonic fluids 4

Pediatric Head Trauma

The American Academy of Pediatrics recommends ondansetron as first-line for head trauma with nausea/vomiting:

• Superior safety profile compared to metoclopramide, particularly regarding effects that could interfere with neurological monitoring 4
• Dopamine antagonists like metoclopramide should not be used for multiple consecutive days due to high incidence of dystonic reactions 4

Critical Safety Considerations

QT Prolongation Risk

Exercise special caution in children with cardiac disease:

• Ondansetron can prolong QT interval; avoid in congenital long QT syndrome 2, 4, 3
• Before administration:
  • Ensure adequate hydration 2, 4
  • Monitor electrolytes, particularly potassium and magnesium 2, 4
  • Obtain baseline ECG if known cardiac disease 4
• ECG monitoring recommended in patients with electrolyte abnormalities, congestive heart failure, bradyarrhythmias, or concurrent QT-prolonging medications 3

Hepatic Impairment

In severe hepatic impairment (Child-Pugh score ≥10), do not exceed 8 mg total daily dose. 2, 3

Serotonin Syndrome

Rare but serious risk, particularly with concomitant serotonergic drugs (SSRIs, SNRIs, MAOIs, fentanyl, tramadol). 3

Why Ondansetron Over Alternatives

Ondansetron should be the antiemetic of first choice instead of metoclopramide:

• Superior efficacy in controlling nausea and vomiting 1
• Significantly better safety profile 1
• Lower risk of serious extrapyramidal reactions that can occur with metoclopramide 1
• Better acceptance of oral liquids and fewer side effects compared to metoclopramide and bromopride 6

Metoclopramide produces extrapyramidal reactions and sedation, with highly variable pharmacodynamics in pediatric patients. 7

Alternative Agents When Ondansetron Contraindicated

If ondansetron is contraindicated due to QT concerns or allergy:

• Granisetron is the most logical alternative, sharing the same favorable neurological safety profile 4
• Dexamethasone can be highly effective for nausea, particularly when combined with other antiemetics, and may serve dual purposes in head trauma (reducing cerebral edema while providing antiemetic effects) 4