Uses of Zafirlukast

Zafirlukast is a drug to treat asthma symptoms. It works as a leukotriene receptor antagonist (LTRA) by inhibiting the 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, you must consult your physician if you experience anything unusual while taking this medication.

Warnings & Precautions

Before taking zafirlukast:
  • tell your doctor and pharmacist in case 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 in case you suffer or have ever suffered from liver disease.
  • tell your doctor in case 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 also affect your mental health. Seek immediate treatment in case you experience agitation, aggressiveness, anxiety, depression, hallucinations, insomnia, irritability, restlessness, strange dreams, suicidal behavior, or tremors.

Dosage of Zafirlukast

Zafirlukast comes as a tablet that is 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 time each day.

Zafirlukast is not meant to treat a sudden asthma attack, 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 doctor’s and laboratory appointments, as certain tests may be required to monitor your body’s response to zafirlukast.