Zafirlukast is a medication used to manage and prevent asthma symptoms. It belongs to a class of drugs known as leukotriene receptor antagonists, which work by blocking substances in the body called leukotrienes that cause inflammation and constriction of the airways. By reducing these effects, zafirlukast helps improve breathing and decrease the frequency of asthma attacks. This medication is typically taken orally, and it is important for patients to follow their healthcare provider's instructions regarding dosage. Common side effects may include headache, nausea, and abdominal pain. Patients should also inform their doctor of any other medications they are taking to avoid potential interactions.