CLASS: Antiemetic agent

Mechanism of Action:

Selectively blocks serotonin 5-HT3 receptors located in the CNS at the chemoreceptor trigger zone and in the peripheral nervous system on nerve-terminals of the vagus nerve

Indications for use: 

Nausea and vomiting


Use with caution in patients with hepatic impairment Avoid use in patients with long QT syndrome

Adverse Reactions:

CNS: Headache, malaise, fatigue, dizziness, fever, sedation, extrapyramidal syndrome

CV: Chest pain, arrhythmias
Resp: Hypoxia
GI/Hepatic: Diarrhea, constipation, abdominal pain, xerostomia, decreased appetite Skin: Rash

NOTES ON ADMINISTRATION Incompatibilities/Drug Interactions:

Inducers or inhibitors of P450 drug metabolizing enzymes may alter the clearance of Ondansetron. No dosage adjustment is recommended.

Adult Dosage:

4 – 8 mg IV slow push over 2 – 5 minutes 8 mg PO ODT or tablet

Pediatric Dosage: (1 month to 12 years old)

Greater than 40 kg- 4 mg IV slow push over 2 – 5 minutes Less than 40 kg- 0.1 mg/kg IV slow push over 2 – 5 minutes 4-12 years old 4 mg PO ODT or ODT

Route of Administration:

IV, IM, PO Onset of Action:

Unknown but probably 10 to 30 minutes Peak effects:

Unknown Duration of Action:

Half life is approximately 4 hours. Exact duration unknown but appears to be prolonged compared to half-life

Dosage Forms/Packaging:

4 mg/2 mL vial
4 or 8 mg ODT or tablet

Arizona Drug Box Standard Minimum Supply: 

Optional- 4 mg 

© Matt Dillard 2012