Adult: Prophylaxis and maintenance therapy: 20 mg bid. Recommended therapeutic indications may vary between countries (refer to local or specific product guidelines). Child: 5-11 years 10 mg bid; ≥12 years Same as adult dose. Recommended therapeutic indications may vary between countries (refer to local or specific product guidelines).
Hepatic Impairment
Contraindicated.
Administration
Should be taken on an empty stomach.
Contraindications
Hepatic impairment including hepatic cirrhosis.
Special Precautions
Not indicated for use in acute asthma attacks (including status asthmaticus). Children and elderly. Pregnancy and lactation.
Adverse Reactions
Significant: Hepatotoxicity (e.g. hyperbilirubinaemia, hepatitis); neuropsychiatric events (e.g. insomnia, depression); infections predominantly affecting the respiratory tract (mostly to >55 years of age). Rarely, systemic eosinophilia (sometimes manifesting with clinical features of vasculitis consistent with eosinophilic granulomatosis with polyangiitis [formerly known as Churg-Strauss syndrome]). Blood and lymphatic system disorders: Agranulocytosis. Gastrointestinal disorders: Nausea, vomiting, abdominal pain, diarrhoea, dyspepsia. General disorders and administration site conditions: Fever, oedema, malaise. Immune system disorders: Hypersensitivity reactions (e.g. urticaria, angioedema, pruritus, rashes with or without blistering). Investigations: Increased serum ALT. Musculoskeletal and connective tissue disorders: Myalgia, arthralgia, back pain. Nervous system disorders: Headache, dizziness. Vascular disorders: Bleeding, bruising. Potentially Fatal: Hepatic failure leading to liver transplantation.
Monitor LFTs periodically. Closely monitor for signs and symptoms of hepatic injury and neuropsychiatric symptoms or behavioural changes.
Overdosage
Symptoms: Rash and stomach upset. Management: Supportive treatment. Empty the stomach by inducing emesis or performing gastric lavage. May administer activated charcoal to prevent further absorption of unrecovered drug.
Drug Interactions
May enhance the anticoagulant activity of warfarin resulting in prolonged prothrombin time. May reduce serum concentration with theophylline, terfenadine, and erythromycin. Increased serum concentration with fluconazole and high doses of aspirin.
Food Interaction
Decreased rate and extent of absorption with food.
Action
Description: Mechanism of Action: Zafirlukast, an antiasthmatic agent, is a competitive and selective leukotriene-receptor antagonist (LTRA) of leukotriene D4 and E4 (LTD4 and LTE4), components of slow-reacting substance of anaphylaxis (SRSA). The production, stimulation, and receptor occupation of cysteinyl leukotriene have been correlated with the pathophysiology of asthma including smooth muscle constriction, airway oedema, and altered cellular activity related with the inflammatory process which contribute to the signs and symptoms of asthma. Pharmacokinetics: Absorption: Rapidly absorbed from the gastrointestinal tract. Food reduces the rate and extent of absorption. Time to peak plasma concentration: Approx 3 hours. Distribution: Enters breast milk. Plasma protein binding: Approx 99%, mainly to albumin. Metabolism: Extensively metabolised in the liver mainly by CYP2C9 isoenzyme into hydroxylated metabolites. Excretion: Mainly via faeces (approx 90%, as unchanged drug and metabolites); urine (approx 10%, as metabolites). Elimination half-life: Approx 10 hours (range 8-16 hours).
Chemical Structure
Zafirlukast Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 5717, Zafirlukast. https://pubchem.ncbi.nlm.nih.gov/compound/Zafirlukast. Accessed Feb. 27, 2024.
Storage
Store between 20-25°C. Protect from light and moisture.
R03DC01 - zafirlukast ; Belongs to the class of leukotriene receptor antagonists. Used in the systemic treatment of obstructive airway diseases.
References
Accolate Tablets (AstraZeneca Pharmaceuticals LP). U.S. FDA. https://www.fda.gov. Accessed 10/01/2024.Anon. Zafirlukast. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 10/01/2024.Anon. Zafirlukast. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 10/01/2024.Buckingham R (ed). Zafirlukast. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 10/01/2024.Zafirlukast Tablet, Film Coated (Aurobindo Pharma Limited). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 10/01/2024.Zafirlukast. Gold Standard Drug Database in ClinicalKey [online]. Elsevier Inc. https://www.clinicalkey.com. Accessed 21/02/2024.
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