Zafirlukast: A Leukotriene Receptor Antagonist for Asthma and Allergies
Zafirlukast is a leukotriene receptor antagonist (LTRA) used to manage asthma and allergic rhinitis. By blocking leukotrienes—chemicals in the body that contribute to inflammation and bronchoconstriction—Zafirlukast helps to reduce inflammation in the airways, making it easier to breathe.
Mechanism of Action
Zafirlukast works by selectively inhibiting the leukotriene receptors (specifically CysLT1), which are responsible for the inflammatory responses that occur during asthma and allergy attacks. This reduces airway inflammation, bronchoconstriction, and mucous production, leading to improved breathing.
Indications
● Asthma: Zafirlukast is used as a maintenance treatment for asthma to reduce inflammation and prevent asthma attacks.
● Allergic Rhinitis: It is used off-label to treat symptoms of allergic rhinitis, including nasal congestion, itchiness, and sneezing.
Dosage and Administration
● Adults and Children (>=12 years): The recommended dosage is 20 mg twice daily for asthma management.
● Children (5–11 years): The recommended dosage is 10 mg twice daily.
● Administration: Zafirlukast should be taken on an empty stomach, at least 1 hour before or 2 hours after meals.
Side Effects
● Common Side Effects: Headache, diarrhea, and abdominal pain.
● Serious Side Effects: Liver enzyme elevation, which may indicate liver dysfunction, and allergic reactions like rash, fever, or breathing difficulties. Rarely, it may cause neutropenia (a decrease in white blood cells).
Pregnancy Category: Category C – Zafirlukast should be used during pregnancy only if the benefits justify the potential risks to the fetus.
Common Brands: Accolate, Zufair