Uses of Zafirlukast

Zafirlukast is used to prevent the symptoms of asthma. As a leukotriene receptor antagonists (LTRA), it works by blocking natural substances that cause the airways to swell and tighten.

Side Effects of Zafirlukast

  • difficulty breathing or swallowing
  • fatigue/lack of energy
  • flu-like symptoms
  • hand or foot pain pain; tingling or numbness in the hands or feet
  • itching
  • lack of appetite
  • loss of voice
  • nausea or stomach pain
  • rash
  • swollen of the face, eyes, lips, tongue, or throat
  • yellowing of the eyes or skin

Zafirlukast may cause other side effects. Consult your physician if you experience anything unusual while taking this medication.

Warnings & Precautions

Before taking zafirlukast:

  • tell your doctor and pharmacist if you have any medication allergies.
  • tell your doctor and pharmacist about any medications (over-the-counter or prescription) and supplements you are taking. It is especially important to mention anticoagulants (“blood thinners”) [e.g., warfarin (Coumadin); aspirin or products that contain aspirin; calcium channel blockers [e.g., amlodipine (Norvasc, in Caduet), diltiazem (Cardizem, Tiazac), felodipine (Plendil), isradipine (Dynacirc), nicardipine (Cardene), nifedipine (Adalat, Procardia, others), nimodipine (Nimotop), nisoldipine (Sular), verapamil (Calan, Covera, Isoptin, Verelan)]; carbamazepine (Equetro, Tegretol); cisapride (Propulsid) (not available in the U.S.)]; cyclosporine (Neoral, Sandimmune); erythromycin (E.E.S, Erythrocin); phenytoin (Dilantin); theophylline (Theo-Dur, others); and tolbutamide.
  • tell your doctor if you suffer or have ever suffered from liver disease.
  • tell your doctor if you plan to become pregnant, are pregnant, or are breastfeeding. Call you doctor immediately if you become pregnant during treatment.
  • you should know that zafirlukast may affect your mental health. Seek immediate treatment if you experience agitation, aggressiveness, anxiety, depression, hallucinations, insomnia, irritability, restlessness, strange dreams, suicidal behavior, or tremors.

Dosage of Zafirlukast

Zafirlukast comes as a tablet to be taken orally. It is usually taken twice a day, either 1 hour before or 2 hours after a meal. Be sure to take zafirlukast exactly as directed and to take it at roughly the same times each day.

Zafirlukast is not intended to treat a sudden asthma attack. to treat a sudden attack of asthma symptoms. Your doctor to prescribe a fast-acting inhaler instead.

Continue to take all medications prescribed to treat your asthma unless your doctor tells you otherwise.

Zafirlukast cannot cure asthma. Continue to take it even if you feel fine.


Keep all appointments with your doctor and the laboratory, as certain tests may be needed to monitor your body’s response to zafirlukast.