What is zafirlukast?
Zafirlukast is a leukotriene (loo-koe-TRY-een) inhibitor. Leukotrienes are chemicals your body
releases when you breathe in an allergen (such as pollen). These chemicals cause swelling in your lungs
and tightening of the muscles around your airways, which can result in asthma symptoms.
Zafirlukast is used to treat and prevent asthma attacks in adults and children as young as 5 years
old.
Do not give this medication to a child without a doctor's advice.
Zafirlukast may also be used for other purposes not listed in this medication guide.
What should I discuss with my healthcare provider before taking zafirlukast?
Do not use this medication if you are allergic to zafirlukast.
Before using zafirlukast, tell your doctor if you are allergic to any drugs (especially aspirin), or if
you have liver disease. You may not be able to use zafirlukast, or you may need dosage adjustments or
special tests during treatment.
The chewable tablet form of this medication may contain up to 0.842 milligrams of
phenylalanine. Talk to your doctor before using this form of zafirlukast if you have phenylketonuria
(PKU).
FDA pregnancy category B. This medication is not expected to be harmful to an unborn
baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.
Zafirlukast can pass into breast milk and may harm a nursing baby. Do not use this
medication without telling your doctor if you are breast-feeding a baby.
How should I take zafirlukast?
Take this medication exactly as it was prescribed for you. Do not take the medication in larger
amounts, or take it for longer than recommended by your doctor. Follow the directions on your
prescription label.
Zafirlukast is usually taken once daily in the evening for prevention of asthma or allergy
symptoms. Follow your doctor's instructions.
Take zafirlukast on an empty stomach, at least 1 hour before or 2 hours after a meal.
Do not use zafirlukast to treat an asthma attack that has already begun. It will not work fast
enough to reverse your symptoms. Use only a fast-acting inhalation medication to treat an asthma
attack. Talk with your doctor if any of your asthma medications do not seem to work as well in treating
or preventing asthma attacks.
For best results, keep using zafirlukast as directed. Talk with your doctor if your symptoms
do not improve after several weeks of treatment.
Asthma is often treated with a combination of different drugs. To best treat your condition, use
all of your medications as directed by your doctor. Be sure to read the medication guide or patient
instructions provided with each of your medications. Do not change your doses or medication schedule
without advice from your doctor, even if you have no asthma symptoms.
Call your doctor right away if you feel that this medicine is not working as well as usual, or if it
makes your condition worse. If it seems like you need to use more of any of your medications in a
24-hour period, talk with your doctor.
Store zafirlukast at room temperature away from moisture and heat.
What happens if I miss a dose of zafirlukast?
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the
missed dose and take the medicine at your next regularly scheduled time.
Do not
take
extra medicine to make up the missed dose.
Where can I get more information about zafirlukast?
Your pharmacist has information about zafirlukast written for health professionals that you may read.
What are the possible side effects of zafirlukast?
Get emergency medical help if you have any of these
signs of an allergic
reaction:
hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have any of these serious side effects:
-
worsening asthma symptoms;
-
mood or behavior changes, anxiety, depression, or thoughts
about suicide or hurting yourself;
-
skin rash, bruising, severe tingling, numbness, pain, muscle
weakness; or
-
nausea, stomach pain, loss of appetite, itching, dark urine,
clay-colored stools, jaundice (yellowing of the skin or eyes).
Less serious side effects may include:
-
headache;
-
nausea, vomiting, diarrhea, stomach pain;
-
weakness;
-
dizziness;
-
muscle pain; or
-
fever, sore throat, cold symptoms.
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.
What is the most important information I should know about zafirlukast?
Do not use zafirlukast to treat an asthma attack that has already begun. It will not work fast
enough to reverse your symptoms. Use only a fast-acting inhalation medication to treat an asthma
attack. Talk with your doctor if any of your asthma medications do not seem to work as well in treating
or preventing asthma attacks.
It may take up to several weeks of using this medicine before your symptoms improve. For
best results, keep using the medication as directed. Talk with your doctor if your symptoms do not
improve after several weeks of treatment.
Call your doctor right away if you feel that this medicine is not working as well as usual, or if it
makes your condition worse. If it seems like you need to use more of any of your medications in a
24-hour period, talk with your doctor.
What should I avoid while taking zafirlukast?
Avoid situations or activities that may trigger an asthma attack.
What other drugs will affect zafirlukast?
Before using zafirlukast, tell your doctor if you are using any of the following drugs:
-
aspirin;
-
a blood thinner such as warfarin (Coumadin);
-
tolbutamide (Orinase);
-
erythromycin (E.E.S., E-Mycin, Ery-Tab, Erythrocin);
-
theophylline (Elixophyllin, Respbid, Slo-Bid, TheoDur, and
others);
-
carbamazepine (Carbatrol, Tegretol); or
-
phenytoin (Dilantin).
This list is not complete and there may be other drugs that can interact with
zafirlukast. Tell your doctor about all the prescription and over-the-counter medications you use. This
includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using
a new medication without telling your doctor.
What happens if I have an overdose of zafirlukast?