Uses
Asthma
Prevention and long-term symptomatic management of asthma in adults and pediatric patients >5 years of age.
In patients with mild persistent asthma, low doses of orally inhaled corticosteroids considered first-line agents for long-term control; alternative agents, including a leukotriene modifier (e.g., zafirlukast, montelukast), may be used but are less effective than inhaled corticosteroids and are not preferred as initial therapy.
In patients with moderate persistent asthma, low- to medium-dose inhaled corticosteroids with a long-acting β2-agonist bronchodilator are preferred for long-term control; alternative agents, including a leukotriene modifier (e.g., zafirlukast, montelukast), can be added to a low or medium dosage of corticosteroids, but these options are less effective.
Therapy with zafirlukast may be especially useful in patients who are unable or unwilling to comply with therapy using inhaled drugs (e.g., children).
Allergic Rhinitis
Has been used for symptomatic management of seasonal allergic rhinitis†.
Exercise-induced Bronchospasm
Has been used for the prevention of exercise-induced bronchospasm†.
Leukotriene modifiers not included as first-line agents or as alternative agents to orally inhaled β2-adrenergic agonists in current guidelines.
Dosage and Administration
Administration
Oral Administration
Administer twice daily on an empty stomach (i.e., at least 1 hour before or two hours after meals).
Dosage
Pediatric Patients
Asthma
Oral
Children 5–11 years of age: 10 mg twice daily.
Children ≥12 years of age: 20 mg twice daily.
Adults
Asthma
Oral
20 mg twice daily.
Special Populations
Dosage in Hepatic Impairment
Clearance may be decreased. Dosage reduction may be necessary; however, the manufacturer currently makes no specific recommendations for dosage adjustment. Not evaluated in patients with hepatitis or in long-term studies in patients with cirrhosis. (See Special Populations under Absorption and under Elimination in Pharmacokinetics and see Hepatic Impairment.)
Dosage in Renal Impairment
Dosage adjustment not required.
Geriatric Patients
Dosage adjustment not required. (See Special Populations under Absorption and under Elimination in Pharmacokinetics.)
Cautions
Contraindications
Known hypersensitivity to zafirlukast or any ingredient in the formulation.
Warnings/Precautions
Warnings
Hepatic Effects
Hepatic dysfunction, including increases in liver enzyme concentrations, hepatitis, and/or hyperbilirubinemia, reported. Zafirlukast-induced hepatotoxicity usually is reversible following discontinuance of the drug.
Serious and potentially fatal hepatoxicity, including fulminant hepatitis and liver failure, reported rarely.
Monitor closely for signs and symptoms of hepatic impairment; consider performing liver function tests (e.g., serum AST and ALT) periodically. Advise patients to immediately contact their clinician if they notice signs and symptoms of liver dysfunction.
Discontinue therapy if signs and/or symptoms suggestive of liver dysfunction occur; immediately perform liver function tests (i.e., serum ALT) and manage patient accordingly.
Do not reinitiate therapy if results of liver function tests are consistent with hepatic dysfunction or if zafirlukast was discontinued because of hepatic dysfunction when no other attributable cause could be identified.
Acute Asthma
Do not use for relief of acute bronchospasm (including status asthmaticus); zafirlukast can be continued during acute exacerbations of asthma, but it will not provide immediate symptomatic relief. Patients who experience exacerbations of asthma should continue their usual regimen of inhaled β2–adrenergic agonists for prophylaxis and have a short-acting orally inhaled β2-adrenergic agonist available for rescue.
Interactions
Concomitant use with warfarin results in a clinically important increase in PT. (See Specific Drugs under Interactions.)
Sensitivity Reactions
Eosinophilic and Churg-Strauss Syndrome
Systemic eosinophilia, eosinophilic pneumonia, or clinical features of vasculitis consistent with Churg-Strauss syndrome reported rarely in patients receiving leukotriene modifiers; these events usually associated with reduction (tapered dosage) or withdrawal of oral or high-dose inhaled corticosteroid therapy. Be alert to the development of eosinophilia, vasculitic rash, worsening pulmonary symptoms, cardiac complications, and/or neuropathy; causal relationship not established.
General Precautions
Concomitant Corticosteroid Therapy
Do not abruptly substitute zafirlukast for oral or inhaled corticosteroids. Orally inhaled corticosteroid requirements may be reduced during zafirlukast therapy; undertake only gradual (e.g., at 2-week intervals) reduction of corticosteroid dosage.
Specific Populations
Pregnancy
Category B.
American College of Allergy, Asthma, and Immunology (ACAAI) and American College of Obstetrics and Gynecologists (ACOG) recommend that use of zafirlukast during pregnancy be limited to patients with recalcitrant asthma who have shown a uniquely favorable response to the drug prior to pregnancy.
Lactation
Distributed into milk. Discontinue nursing or the drug.
Pediatric Use
Safety demonstrated in children 5–11 years of age; efficacy extrapolated from demonstrated efficacy in adults with asthma and the likelihood that the disease course, pathophysiology, and drug's effect are similar between the two populations.
Safety and efficacy not established in children <5 years of age.
Increased systemic exposure and AUC, reflecting decreased clearance in children relative to adults.
Effect on growth in pediatric patients not evaluated in clinical studies to date.
Geriatric Use
Possible increased incidence of infection (e.g., pharyngitis, rhinitis) compared with younger adults.
Hepatic Impairment
Decreased clearance; dosage reduction may be necessary. (See Special Populations under Absorption and under Elimination in Pharmacokinetics.)
Common Adverse Effects
Headache, infection, nausea, diarrhea.
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