Zafirlukast: Nursing Drug Guide, Hepatotoxicity & Hold Rules

Zafirlukast is an oral leukotriene receptor antagonist (LTRA). U.S. labeling covers 10 mg and 20 mg film-coated tablets.

• Brand: Accolate (and multiple generics)
• Strengths: 10 mg tablet (commonly ages 5–11) and 20 mg tablet (adults and children ≥12 years)
• Not interchangeable with: montelukast or other leukotriene modifiers—different dosing, food rules, and safety profile
• Duplicate therapy risk: Do not combine two LTRAs without prescriber intent

Per U.S. prescribing information, zafirlukast is indicated for the prophylaxis and chronic treatment of asthma in adults and children 5 years and older.

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Improvement in daytime symptoms, nighttime awakenings, and rescue inhaler use may begin within one week in clinical trials, but nurses must still prioritize liver safety and rescue planning over symptom-only focus.

Zafirlukast selectively antagonizes cysteinyl leukotriene receptors (LTD₄ and LTE₄), reducing leukotriene-driven bronchoconstriction, airway edema, and inflammatory cell activity in asthma.

It is a controller, not a bronchodilator. Hepatic metabolism via CYP2C9 (and inhibition of CYP3A4/CYP2C9 at clinical concentrations) explains why nurses must watch liver function and warfarin/theophylline interactions even when asthma seems stable.

Take at least 1 hour before or 2 hours after meals—food reduces bioavailability about 40%. Dosing must match prescriber order, age, and current prescribing information.

Missed dose: Not specified in the reviewed prescribing information.

Elderly (≥65 years): Clearance reduced (~2–3× higher C_max and AUC); labeling used 20 mg BID in trials without increased overall adverse events—still monitor closely for hepatotoxicity and infections reported more often in elderly zafirlukast patients.

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• Correct patient, drug, strength (10 vs 20 mg), route, and empty-stomach timing
• Liver history: cirrhosis, hepatitis, alcohol-related liver disease, or prior drug-induced injury → contraindicated
• Baseline symptoms: RUQ pain, dark urine, jaundice, anorexia, flu-like illness
• Available labs: trend AST/ALT if clinically indicated per prescriber protocol
• Rescue plan: short-acting beta-agonist for acute shortness of breath—zafirlukast does not replace it
• Warfarin or CYP2C9 substrates: interaction check and INR plan
• Theophylline co-therapy—rare toxicity reports after zafirlukast addition
• Oral corticosteroid taper: watch for eosinophilic/vasculitic syndrome features
• Breastfeeding status—drug contraindicated while nursing per labeling
• Medication reconciliation for duplicate LTRA or home Accolate bottles

• Hypersensitivity to zafirlukast or any inactive ingredient
• Hepatic impairment, including cirrhosis
• Breastfeeding—excreted in breast milk; labeling advises alternative asthma therapy for nursing mothers

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• Oral tablet swallowed whole with water unless pharmacy directs otherwise
• Give ≥1 hour before or ≥2 hours after meals; do not administer with breakfast/lunch trays without spacing
• Schedule twice daily at consistent intervals (e.g., 0700 and 1900 fasting windows)
• Continue during mild asthma exacerbations per labeling—but treat acute attacks with bronchodilator therapy
• Document empty-stomach adherence on MAR

• Reduced daytime asthma symptoms, nighttime awakenings, and rescue inhaler use over days to weeks
• Improved morning peak expiratory flow in trial populations
• Persistent wheezing or rising rescue use suggests inadequate control—notify prescriber; do not compensate by giving with food or extra doses

• Hepatic injury cues: RUQ pain, jaundice, dark urine, anorexia, flu-like symptoms, pruritus → stop zafirlukast, obtain ALT, notify prescriber urgently
• Acute asthma attack—escalate bronchodilator/emergency pathway; zafirlukast is not acute rescue
• Hypersensitivity—urticaria, angioedema, blistering rash; consider anaphylaxis pathway
• Eosinophilia with vasculitic rash, neuropathy, or cardiac symptoms—especially during oral prednisone reduction
• Neuropsychiatric changes—insomnia, depression; notify prescriber per labeling
• INR supratherapeutic after starting zafirlukast on warfarin

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Overdosage reports include doses up to ~200 mg with predominant symptoms of rash and upset stomach. No consistent acute toxic syndrome is described in labeling.

Antidote

No specific antidote is listed in the reviewed prescribing information. Employ supportive care, remove unabsorbed drug if appropriate, and monitor clinically. Contact local poison control or medical toxicology services per facility protocol and local emergency guidance.

• Zafirlukast vs montelukast—both LTRAs but different doses, food rules, and safety emphasis; read back generic name
• Accolate vs Singulair—brand confusion between leukotriene modifiers
• 10 mg vs 20 mg white round tablets—verify imprint and pediatric vs adult order
• Controller vs rescue—do not pull zafirlukast during code wheeze when albuterol is indicated
• No specific LASA pair is named in labeling; standard independent double-check still applies

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Monitor

• Clinical hepatic symptoms at every contact
• ALT (and hepatic panel if ordered) when symptoms or baseline risk
• Asthma control: symptoms, nocturnal awakenings, rescue inhaler use, peak flow if used
• INR on warfarin co-therapy after initiation or dose change
• Mood/sleep if neuropsychiatric symptoms reported
• Signs of eosinophilic vasculitis during steroid tapers

Document

• Dose, time, empty-stomach adherence, and indication
• Baseline liver history and allergy status
• Hepatic symptom teaching and patient/caregiver verbalization
• Hold actions, ALT results, and prescriber notification
• INR values when anticoagulated

• Take every day for asthma prevention—even when feeling well
• Take 1 hour before or 2 hours after food; ask nurses to help schedule around meals
• Not for sudden breathing emergencies—use rescue inhaler and emergency care per action plan
• Report immediately: RUQ pain, yellow skin/eyes, dark urine, persistent nausea, unusual tiredness, itching
• Do not stop other asthma medicines unless prescriber directs
• Women who are breastfeeding should not take zafirlukast—discuss alternatives
• Tell providers about warfarin, theophylline, erythromycin, aspirin, and fluconazole
• Report mood changes, insomnia, or depression

Do not give and contact the prescriber/pharmacist when:

Hold parameters may vary by institutional protocol. Follow prescriber orders, pharmacy guidance, and facility policy.

Practice NCLEX-style clinical judgment practice for zafirlukast using a tabbed case (MAR, labs, history, nursing notes), then priority action, select-all-that-apply cues, lab trend interpretation, matrix urgency sorting, clinical judgment, and documentation cloze—recognise cues → analyse → prioritise → act → evaluate outcomes (hepatotoxicity hold rules, empty-stomach dosing, and warfarin interaction).

This medication guide is written and reviewed using NurseOnShift editorial and clinical review standards.

• Editorial Policy
• Medical Review Process
• Disclaimer

Educational use only. This content does not replace clinical judgment, prescriber orders, pharmacist guidance, product labeling, or institutional protocols.