Zafirlukast


Concise Prescribing Info
Indications/Uses
Chronic asthma.
Dosage/Direction for Use
Adult : PO 20 mg bid.
Dosage Details
Oral
Chronic asthma
Adult: 20 mg bid.
Child: 5-11 years old 10 mg bid. ≥12 years old Same as adult dose.
Hepatic Impairment
Contraindicated.
Administration
Should be taken on an empty stomach. Take at least 1 hr before or 2 hr after meals.
Contraindications
Hepatic impairment including hepatic cirrhosis.
Special Precautions
Not indicated for use in the reversal of bronchospasm in acute asthma attacks. Avoid abruptly substitution to oral or inhaled corticosteroids. Renal impairment. Pregnancy and lactation.
Adverse Reactions
Systemic eosinophilia, eosinophilic pneumonia or w/ clinical features of systemic vasculitis consistent w/ Churg-Strauss syndrome; neuropsychiatric adverse events (e.g. insomnia, depression); headache, resp tract infection, GI disturbances, arthralgia, myalgia, fever, malaise, insomnia, dizziness, elevated liver enzyme values, hypersensitivity reactions (e.g. rashes, pruritus, urticaria, angioedema), agranulocytosis, bleeding, bruising, oedema.
Potentially Fatal: Severe hepatotoxicity.
MonitoringParameters
Monitor for improvements in air flow; monitor closely for sign/symptoms of hepatic injury; periodic monitoring of LFTs.
Overdosage
Symptoms: Rash and stomach upset. Management: Supportive and symptomatic treatment. Empty the stomach by inducing emesis or by gastric lavage. May administer activated charcoal to prevent absorption of unrecovered drug.
Drug Interactions
May enhance anticoagulant activity of warfarin resulting to increased prothrombin time. Decreased plasma levels w/ theophylline, terfenadine and erythromycin. Increased plasma levels w/ fluconazole and high dose aspirin.
Food Interaction
Food reduces the rate and extent of absorption.
Action
Description: Zafirlukast is a selective and competitive leukotriene-receptor antagonist (LTRA) of leukotriene D4 and E4 (LTD4 and LTE4), components of slow-reacting substance of anaphylaxis (SRSA). Cysteinyl leukotriene production and receptor occupation have been correlated w/ the pathophysiology of asthma, including airway oedema, smooth muscle constriction, and altered cellular activity associated w/ the inflammatory process, which contribute to the signs and symptoms of asthma.
Pharmacokinetics:
Absorption: Rapidly absorbed from the GI tract. Food reduces the rate and extent of absorption. Time to peak plasma concentration: Approx 3 hr.
Distribution: Volume of distribution: Approx 70 L. Plasma protein binding: Approx 99% (primarily to albumin).
Metabolism: Extensively metabolised in the liver, mainly by CYP2C9 isoenzyme.
Excretion: Mainly via faeces (approx 90%) as unchanged drug and metabolites and urine (approx 10%) as metabolites. Terminal elimination half-life: Approx 10 hr.
Chemical Structure

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Storage
Store between 20-25°C. Protect from light and moisture.
Disclaimer: This information is independently developed by MIMS based on Zafirlukast from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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