Learning About Leukotriene Modifiers

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Leukotriene (say "loo-koh-TRY-een") modifiers are drugs used for asthma and hay fever.

They treat asthma symptoms in adults. And in children, they improve how well the lungs work. They are not used to treat asthma attacks.

They also reduce symptoms of hay fever. These include sneezing and a runny or stuffy nose.


  • Montelukast (Singulair)
  • Zafirlukast (Accolate)
  • Zileuton (Zyflo)

Side effects

  • Vomiting.
  • Diarrhea.
  • A headache.

You may have other side effects or reactions. Check the information that comes with your medicine.

What to know about taking these medicines

  • These drugs may help if your asthma is caused by exercise, aspirin, or allergies.
  • You may need to have blood tests during the first 6 months of treatment. The tests check for liver damage.
  • Take your medicines exactly as prescribed. Call your doctor if you think you are having a problem with your medicine.
  • Check with your doctor or pharmacist before you use any other medicines. This includes over-the-counter drugs. Make sure your doctor knows all of the medicines you take. This includes vitamins, herbs, and supplements. Taking some drugs together can cause problems.

The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.