Zafirlukast is a leukotriene (loo-koe-TRY-een) inhibitor that is used to prevent asthma attacks in adults and children as young as 5 years old.

Zafirlukast may also be used for purposes not listed in this medication guide.

Tell your doctor right away if you have signs of blood vessel inflammation: flu-like symptoms, severe sinus pain, a skin rash, numbness or a "pins and needles" feeling in your arms or legs.

Stop taking this medicine and call your doctor right away if you have any unusual changes in mood or behavior (such as agitation, confusion, depression, sleep problems, compulsive behaviors, hallucinations, or suicidal thoughts or actions).

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Zafirlukast is not a fast-acting rescue medicine for asthma attacks. Seek medical attention if your breathing problems get worse quickly, or if you think your medications are not working.

Take on an empty stomach, at least 1 hour before or 2 hours after a meal.

Your dose needs may change due to surgery, illness, stress, or a recent asthma attack. Do not change your dose or stop using asthma medication without your doctor's advice.

Keep using zafirlukast as directed, even if you have no asthma symptoms.

If you take oral steroid medicine, do not stop it suddenly. Ask your doctor about tapering your dose.

Store at room temperature away from moisture, heat, and light. Keep the bottle tightly closed when not in use.

Usual Adult Dose for Asthma -- Maintenance:

-20 mg orally twice a day, 1 hour before or 2 hours after meals

Comments:
-A dose of 20 mg twice daily was not associated with an increase in the overall incidence of adverse events or withdrawals in elderly patients.

Use: Prophylaxis and chronic treatment of asthma

Usual Pediatric Dose for Asthma -- Maintenance:

Less than 5 years: The safety and effectiveness has not been established.

5 to 11 years:
-10 mg orally twice a day, 1 hour before or 2 hours after meals

12 years or older:
-20 mg orally twice a day, 1 hour before or 2 hours after meals

Use: Prophylaxis and chronic treatment of asthma

You should not use zafirlukast if you are allergic to it, or if you have liver disease (including cirrhosis).

Tell your doctor if you have ever had liver disease.

Not approved for use by anyone younger than 5 years old.

The chewable tablet may contain phenylalanine and could be harmful if you have phenylketonuria (PKU).

It is not known if zafirlukast will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

You should not breastfeed while using zafirlukast.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from light, excess heat, and moisture (not in the bathroom) .

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

Unless your doctor tells you otherwise, continue your normal diet.

Avoid situations or activities that may trigger an asthma attack.

Get emergency medical help if you have signs of an allergic reaction: hives, blisters, severe itching; difficult breathing; swelling of your face, lips, tongue, or throat.

Tell your doctor right away if you have signs of blood vessel inflammation: flu-like symptoms, severe sinus pain, a skin rash, numbness or a "pins and needles" feeling in your arms or legs.

Some people using zafirlukast have had new or worsening mental problems. Stop taking zafirlukast and call your doctor right away if you have unusual changes in mood or behavior, such as:

• agitation, aggression, feeling restless or irritable;

• anxiety, depression, confusion, problems with memory or attention;

• stuttering, tremors, uncontrolled muscle movements;

• suicidal thoughts or actions;

• hallucinations, sleep problems, vivid dreams, sleep-walking; or

• compulsive or repetitive behaviors.

Also call your doctor at once if you have:

• worsening or no improvement in your asthma symptoms; or

• liver problems--nausea, loss of appetite, stomach pain (upper right side), tiredness, itching, dark urine, jaundice (yellowing of the skin or eyes).

Common side effects of zafirlukast may include:

• nausea, diarrhea, stomach pain;

• headache; or

• cold symptoms such as stuffy nose, sneezing, sore throat.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your doctor about all your other medicines, especially:

• erythromycin;

• fluconazole;

• theophylline; or

• warfarin, Coumadin, Jantoven.

This list is not complete. Other drugs may affect zafirlukast, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your response to zafirlukast.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.