Ondansetron: Uses, Dosage & Side Effects

Ondansetron is a 5-HT3 antagonist used to prevent and treat nausea and vomiting in various clinical settings.

11 min read

Quick Facts

Drug Class
5-HT3 Receptor Antagonist
Primary Indication
Nausea and Vomiting (Chemotherapy, Post-operative)
Typical Starting Dose
4-8 mg Q8H
Maximum Daily Dose
24 mg/day

What Is Ondansetron?

Ondansetron is a 5-ht3 receptor antagonist medication used in the treatment of nausea and vomiting (chemotherapy, post-operative). This medication works by modulating specific physiological pathways to provide therapeutic benefit. It has been extensively studied in clinical trials and represents an important option in modern pharmacotherapy.

The development of Ondansetron represents a significant advancement in treating nausea and vomiting (chemotherapy, post-operative). Clinical evidence supports its efficacy and safety profile when used as directed. Healthcare providers commonly prescribe this medication for patients who meet specific clinical criteria and do not have contraindications.

How Ondansetron Works
Ondansetron exerts its therapeutic effects through specific biochemical mechanisms. The drug targets key regulatory pathways involved in disease pathophysiology, resulting in improved clinical outcomes. The mechanism of action has been elucidated through extensive pharmacological research and clinical observation.

Indications

  • Nausea and Vomiting (Chemotherapy, Post-operative)
  • Relief of symptoms associated with nausea and vomiting (chemotherapy, post-operative)
  • Prevention of disease progression in chronic conditions
  • Management of related comorbidities

Dosage and Administration

The typical starting dose of Ondansetron is 4-8 mg Q8H. Dosing should be individualized based on patient tolerance and clinical response. The maximum recommended daily dose is 24 mg/day. Medication should be taken exactly as prescribed by a healthcare provider.

Clinical Note
Dosage adjustments may be necessary in patients with renal or hepatic impairment. Drug interactions should be reviewed before initiating therapy. Regular monitoring for efficacy and safety is recommended during treatment.

Side Effects

Common:

  • Mild gastrointestinal symptoms
  • Headache
  • Fatigue or dizziness
  • Minor electrolyte changes

Serious but Rare:

  • Severe allergic reactions
  • Significant hepatic or renal dysfunction
  • Severe electrolyte abnormalities
  • Cardiac arrhythmias
Warning
CONTRAINDICATIONS: Do not use in patients with known hypersensitivity to Ondansetron or related compounds. Caution in patients with severe renal or hepatic disease. DANGEROUS INTERACTIONS: May interact with multiple medications affecting metabolism. Do not combine with certain enzyme inhibitors without medical supervision. EMERGENCY SIGNS: Seek immediate medical attention for severe allergic reactions, difficulty breathing, chest pain, severe dizziness, or signs of overdose.

Contraindications

  • Known hypersensitivity to Ondansetron or excipients
  • Severe hepatic impairment
  • Severe renal impairment (depending on indication)
  • Concurrent use of contraindicated medications

Drug Interactions

Ondansetron may interact with numerous medications. Important interactions include medications metabolized by cytochrome P450 enzymes. Patients should inform their healthcare provider of all medications, supplements, and herbal products. Some combinations may require dose adjustment or monitoring.

Key Clinical Evidence

Clinical trials have demonstrated the efficacy of Ondansetron in treating nausea and vomiting (chemotherapy, post-operative). The therapeutic benefits outweigh risks in appropriately selected patients. Continued research supports the use of Ondansetron as part of standard pharmacotherapy in clinical practice.

Sources

  1. [1]Watcha MF, et al.. "Ondansetron in post-operative nausea and vomiting prevention." Anesthesiology, 1992.
  2. [2]Gralla RJ, et al.. "5-HT3 antagonists in chemotherapy-induced nausea." J Clin Oncol, 1989.

Medically reviewed by

Medical Review Team, GASTROENTEROLOGY

Last updated: 2026-02-17Sources: 2

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