Field medications · Adult & pediatric guidance · ALS

Ondansetron (Zofran)

10-second priorities

ALS
Start here
Treat ongoing nausea/vomiting while assessing airway and perfusion.
Do not miss
Adult orders exclude known/suspected pregnancy.
Next decision
Pediatric: age 4+ fixed ODT pathway; no routine IV or under-4 dose is supplied.

Priority checkpoints. Full criteria, doses and exceptions below.

Adult oral/IV treatment and the pediatric age-4-and-older ODT pathway.

OCEMS source summary · Updated 2026-09-30

Safety sections checked September 30, 2026 · verified with limits. Existing numeric regimens retain their original source context.

Also known as: Zofran. ODT and injectable formulations have separate route instructions.

FIELD REFERENCE

Full criteria & treatment guidance

Indications

  • Nausea/vomiting within the applicable OCEMS adult or pediatric pathway.

Contraindications & local exclusions

  • Injectable label: hypersensitivity to product/components or concomitant apomorphine. Some OCEMS adult pathways exclude known/suspected pregnancy; use the condition-specific order and do not describe pregnancy as a universal label contraindication.

Precautions

  • Avoid in congenital long-QT syndrome; ECG monitoring is recommended for electrolyte abnormalities, CHF, bradyarrhythmias or QT-prolonging drugs. Serotonin syndrome is a warning. ODT and injectable products have distinct instructions.
  • These are selected safety checks, not a complete prescribing monograph. Product labeling and OCEMS authorization answer different questions; confirm the actual product, patient population and applicable order.

Check before giving

  • The adult standing order excludes known or suspected pregnancy.
  • Do not let symptom control replace assessment of dehydration, poor perfusion, or an altered level of consciousness.

Use in OCEMS

  • For ongoing nausea/vomiting in the applicable condition order. Treat associated airway risk and dehydration as well as symptoms.
  • The oral dissolving tablet and IV preparation have different dosing instructions.

Adult / adolescent

Adult / adolescent
Indication / routeDose & limits
ODT8 mg (two 4 mg tablets) dissolved orally, once, when pregnancy is not known or suspected.
IV4 mg IV; may repeat 4 mg once after approximately 3 minutes for continued/recurrent symptoms, when pregnancy is not known or suspected.

Pediatric

  • SO-P-090: children age 4 and older may receive one 4 mg ODT tablet dissolved orally, as tolerated.
  • The cited pediatric nausea standing order does not provide routine IV dosing or an ODT dose below age 4. Do not infer a weight-scaled adult regimen.

Pediatric dose by age / weight

  • SO-P-090 applies to ongoing nausea/vomiting. Age, not weight, determines eligibility for this fixed dose.
Pediatric dose by age / weight
Age / weightPediatric doseRoute / limit
Younger than 4; any weightNo dose in this pediatric standing orderDo not extrapolate from an adult IV dose
Age 4 and older; any eligible pediatric weight4 mgOne ODT tablet dissolved orally as tolerated

Preparation & reassessment

  • Stock includes 4 mg ODT and 4 mg/2 mL IV preparations. Verify the product and route.
  • Keep suction available when needed. Reassess vomiting, airway protection, perfusion, and treatment response; follow the applicable fluid pathway.

VISUAL FIELD REFERENCE

Ondansetron: adult routes and pediatric age limit

Adult & pediatric guidance · ALS

  • 8 mg · once

    Adult ODT

    8 mg (two 4 mg tablets) dissolved orally, once, when pregnancy is not known or suspected.

  • 4 mg · one repeat

    Adult IV

    4 mg IV; may repeat 4 mg once after approximately 3 minutes for continued/recurrent symptoms, when pregnancy is not known or suspected.

  • 4 mg ODT · once

    Pediatric age 4 and older

    SO-P-090: children age 4 and older may receive one 4 mg ODT tablet dissolved orally, as tolerated.

    The cited pediatric nausea standing order does not provide routine IV dosing or an ODT dose below age 4. Do not infer a weight-scaled adult regimen.

  • Do not let symptom control replace assessment of dehydration, poor perfusion, or an altered level of consciousness.

Selected checkpoints; read the complete guide for criteria, exclusions, doses, and ongoing care. I-15 · I-20 · SO-M-060 · SO-P-090

UNDERSTAND THE CARE

Why age, route and indication must be checked independently

The adult oral and IV instructions are different, and the pediatric pathway is a fixed ODT dose with an age threshold. The presence of an injectable product on the ambulance does not establish a routine pediatric IV regimen. Check the relevant exclusions and the ability to tolerate oral treatment.

Teaching diagram: Population: Adult versus age-eligible pediatric pathway.; Route: ODT and IV instructions differ.; Exclusions: Pregnancy and product/clinical restrictions.; Response: Vomiting, airway safety and perfusion.
Ondansetron (Zofran) assessment map. A teaching map of the linked guidance; it is not a complete treatment algorithm.

Applying the guidance

After medication, reassess vomiting, airway protection, mental status and perfusion. Continue the underlying illness and dehydration assessment even if nausea improves. Record the preparation, route, time and total amount; the adult IV repeat instruction is not an automatic repeat instruction for the ODT pathway.

Dose, concentration and volume

Dose, concentration and volume. First establish the authorized dose and its cap. Read the actual concentration using consistent units. Dose divided by concentration gives volume: mg ÷ (mg/mL) = mL. Route, rate, repeat limits and authority must be checked separately.
First establish the authorized dose and its cap. Read the actual concentration using consistent units. Dose divided by concentration gives volume: mg ÷ (mg/mL) = mL. Route, rate, repeat limits and authority must be checked separately.

Diagram text & teaching checkpoints

Population
Adult versus age-eligible pediatric pathway.
Route
ODT and IV instructions differ.
Exclusions
Pregnancy and product/clinical restrictions.
Response
Vomiting, airway safety and perfusion.

Sources for this explanation

Original OCMedic teaching synthesis of the references below. Educational expansion updated ; this is not a new independent clinical-review date. Source-specific dates and limitations remain in the full guidance.

About OCMedic · Editorial approach & corrections

Do not copy the IV repeat into the ODT pathway

Keep formulation, route and repeat permission together. The adult nausea order describes different oral and IV regimens. A permitted IV repeat does not establish an oral-tablet repeat, and the pediatric ODT pathway does not create a routine pediatric IV regimen. Avoid using stock availability to fill an absent instruction.

For example, a patient has already taken the indicated ODT treatment and continues to vomit during transport. Record the product, amount and time, reassess airway protection and perfusion, and follow the appropriate clinical and medical-direction pathway. Do not silently reinterpret the initial treatment as the first half of an IV sequence.

An improvement in nausea should be reported alongside the broader assessment: ongoing vomiting, suction or airway support, signs of dehydration or poor perfusion, and the response to any other indicated care. The adult standing order’s pregnancy wording remains a local pathway restriction; it should not be presented as a universal contraindication for every ondansetron product or setting.

Source: Nausea / Vomiting.

Explore this guide

Related guides

Drug label / general safety

Checked September 30, 2026. Research verification is not independent clinical review.

Product labelONDANSETRON injection, solution ↗

OCEMS sources

I-15 revised March 31, 2026; I-20 revised March 26, 2026. Both implemented April 1, 2026. See linked condition-specific sources.
Source checked September 16, 2026.
Summary updated 2026-09-30.

I-15Adult / Adolescent Standing Order Drug Guide ↗I-20Pediatric Medication Volume Dose by Weight ↗SO-M-060Nausea / Vomiting ↗SO-P-090Nausea / Vomiting - Pediatric ↗

This summary does not replace the complete policy, current system notices, or clinical judgment.

Independent OCMedic summary. Open cited source ↗ Sources, review limits & corrections

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