Printable reference
Ondansetron (Zofran) seasonal dosing
Quick-reference dosing table with safety checks. Use local protocols; see web version for edge cases.
Scan for updates
Verify before giving
- Confirm indication (e.g. gastroenteritis vomiting).
- Confirm weight (kg), age cutoff per local protocol, and formulation (ODT vs liquid).
- Check QT risk (congenital long QT, electrolyte issues, QT meds).
- Confirm single-dose vs repeat dosing plan per pathway; avoid extra doses without guidance.
- Avoid if concern for surgical abdomen/obstruction; reassess if worsening.
Typical oral dosing (common reference)
Common pediatric oral dosing is 0.15 mg/kg once (often rounded), and many ED pathways use weight-banded single dosing.
| Weight band (kg) | Typical single dose | mL per dose (4 mg/5 mL) | Notes |
|---|---|---|---|
| 8–<15 kg | 2 mg | 2.5 mL | 2 mg is often given as oral solution; verify formulation. |
| 15–30 kg | 4 mg | 5 mL | Common single dose (4 mg ODT widely available). |
| >30 kg | 8 mg | 10 mL | Often max single dose in many peds protocols. |
Volume column assumes oral solution 4 mg/5 mL (0.8 mg/mL). Always verify the bottle label. Use your local pathway for repeat dosing / max daily limits.
Safety notes (quick)
- QT prolongation risk: avoid in congenital long QT; use caution with electrolyte abnormalities or other QT-prolonging drugs.
- Many acute gastroenteritis pathways use a single oral dose; avoid extra doses unless advised.
- Reassess if severe/worsening abdominal pain, distention, bilious emesis, or concern for obstruction.
- After symptom control, start oral rehydration per protocol.
Red flags
Seek urgent evaluation (examples)
- Signs of dehydration with inability to keep fluids down
- Bilious emesis, severe/worsening abdominal pain or distention
- Blood in stool or severe lethargy
Call your clinician/pharmacy (examples)
- Questions about the dose, formulation, or concentration
- Child has heart disease, is on QT meds, or has electrolyte issues
- Symptoms persist or worsen despite rehydration plan
Full calculator: www.pedscalc.com/ondansetron
Educational reference only; not medical advice. Verify weight (kg), formulation, and local protocol; use clinician/pharmacy for edge cases.