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Zafirlukast Dosage

Medically reviewed by Last updated on Jun 1, 2023.

Applies to the following strengths: 10 mg; 20 mg

Usual Adult Dose for:

Usual Pediatric Dose for:

Additional dosage information:

Usual Adult Dose for Asthma - Maintenance

  • 20 mg orally twice a day, 1 hour before or 2 hours after meals

  • A dose of 20 mg twice daily was not associated with an increase in the overall incidence of adverse events or withdrawals in elderly patients.

Use: Prophylaxis and chronic treatment of asthma

Usual Pediatric Dose for Asthma - Maintenance

Less than 5 years: The safety and effectiveness has not been established.

5 to 11 years:

  • 10 mg orally twice a day, 1 hour before or 2 hours after meals

12 years or older:
  • 20 mg orally twice a day, 1 hour before or 2 hours after meals

Use: Prophylaxis and chronic treatment of asthma

Renal Dose Adjustments

No adjustment recommended.

Liver Dose Adjustments

Hepatic impairment including cirrhosis: Contraindicated

This drug has not been evaluated in patients with hepatitis or in long-term studies of patients with cirrhosis.


Safety and efficacy have not been established in patients younger than 5 years.

Consult WARNINGS section for additional precautions.


No data available

Other Comments

Administration advice:

  • This drug should be taken at least 1 hour before or 2 hours after meals.
  • Ongoing clinical assessment, including diagnostic evaluations and treatment is recommended.

Storage requirements:
  • Store at controlled room temperature, 20C to 25C (68F to 77F).
  • Protect from light and moisture.

  • This drug is not a bronchodilator and should not be used to treat acute episodes of asthma.

Patient advice:
  • Report immediately any symptoms of hepatic dysfunction (e.g., right upper quadrant abdominal pain, nausea, fatigue, lethargy, pruritus, jaundice, flu-like symptoms, and anorexia).
  • This drug is indicated for the chronic treatment of asthma and should be taken regularly as prescribed, even during symptom-free periods.
  • Patients should not decrease the dose of this drug or stop taking any other antiasthma medications unless instructed by a physician.
  • Notify the physician if neuropsychiatric events occur while using this drug.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.