Ondansteron

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General

  • Type: anti-emetic
  • Dosage Forms:4, 8
  • Common Trade Names: Zofran

Adult Dosing

  • Nausea/Vomiting: 4-8mg q4h, max 24mg a day

Pediatric Dosing

  • Nausea/Vomiting: 0.1mg/kg IV q4h max dose at once:4-8mg, max 24mg
  • Gastroenteritis - Vomiting
    • 8 to 15 kg:
      • 2mg orally disintegrating tablet dissolved orally as a single dose
    • 15 to 30 kg:
      • 4mg orally disintegrating tablet dissolved orally as a single dose
    • Greater than 30 kg:
      • 8mg orally disintegrating tablet dissolved orally as a single dose

Special Populations

  • Pregnancy Rating: C
    • Consider avoiding in 1st trimester; conflicting data regarding possible risk of teratogenicity
    • Newer data argues that ondansetron is not the cause of birth defects[1]
  • Lactation:safety unknown
    • Adult:
  • Renal Dosing:not defined
  • Hepatic Dosing: not defined
    • Pediatric:
  • Hepatic Dosing: not defined
  • Renal Dosing:not defined

Contraindications

  • Allergy to class/drug
  • congenital long QT syndrome

Adverse Reactions

Serious

  • bronchospasm
  • steven-johnson syndrome
  • QT prolongation
  • torsades de pointes
  • serotonin syndrome
  • extrapyramidal SX
  • blindness, transient

Common

  • headache
  • constipation
  • fatigue
  • hypoxia
  • fever
  • urinary retention
  • agitation

Pharmacology

  • Half-life: 4.6-5.7 hour
  • Metabolism: liver
  • Excretion: urine
  • Mechanism of Action:selectively antagonizes serotonin 5-HT3 receptors

See Also

References

  1. Fejzo MS, et al. Ondansetron in pregnancy and risk of adverse fetal outcomes in the United States. Reprod Toxicol. 2016 Jul;62:87-91.