Health Library Leukotriene Pathway Modifiers for Long-Term Control of AsthmaFrom Healthwise

These medications are available as pills and chewable tablets.

Leukotriene pathway modifiers improve lung function and decrease asthma symptoms.

Leukotriene pathway modifiers are used to treat people with persistent asthma who need daily medication to control inflammation of the airways leading to the lungs (bronchial tubes).

These medications may be given along with inhaled corticosteroids to control mild persistent and moderate persistent asthma. They may be especially helpful for people whose asthma is triggered by exercise, aspirin, or allergies.

Different types of medications are often used together in the treatment of asthma. For more information on the medications used in asthma, see:

• Asthma medications for adults, teens, and children older than age 5.
• Asthma medications for children age 5 and younger.

Research indicates that compared with placebo, leukotriene pathway modifiers:

• Reduced symptoms in adults.¹
• Improved lung function in children. There are conflicting reports on whether they improved symptoms.²

However, leukotriene pathway modifiers are not as effective as inhaled corticosteroids, and adding leukotrienes to inhaled corticosteroids is not as effective as adding long-acting beta2-agonists to inhaled corticosteroids.¹

Digestive system side effects, such as vomiting and diarrhea, may occur with zafirlukast. Also, it may interact with other medications.

In rare cases, zafirlukast and zileuton cause liver damage. If the liver is being affected by zafirlukast or zileuton, liver function tests will show increased liver enzyme levels in the blood, usually within the first 2 months of treatment.

Montelukast causes fewer side effects than other leukotriene pathway modifiers. It is less likely to affect the liver, so liver function monitoring is not needed.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

The U.S. National Asthma Education and Prevention Program (NAEPP) recommends leukotriene pathway modifiers as an alternative treatment in people with mild or persistent asthma. The preferred treatment is inhaled corticosteroids and long-acting beta2-agonists.³

People who take zafirlukast and medication to prevent blood clots (such as warfarin) need to have their clotting times checked regularly. When used with blood-thinning medication, zafirlukast can increase the risk of bleeding. Zafirlukast also may cause problems when taken with other medications, such as blood pressure medications, aspirin, and some seizure medications. Make sure your health professional knows that you are taking these medications before you take zafirlukast.

Montelukast can be given to children age 2 and older. It is given once a day. Zafirlukast can be given to children age 5 and older. It is given twice a day. Zileuton has not been approved by the U.S. Food and Drug Administration (FDA) for use in children.

People who are taking zafirlukast or zileuton need to have liver function tests several times during the first 6 months of treatment. People who are taking theophylline along with zileuton may need to take less theophylline.

People who take leukotriene pathway modifiers may be more likely to take their medication regularly because it can be taken orally and has a more immediate effect on symptoms than some other medications such as inhaled corticosteroids.

Leukotriene pathway modifiers are not used to treat asthma attacks.

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Citations

1. Dennis RJ, et al. (2005). Asthma, search date May 2004. Online version of Clinical Evidence (14): 1847–1877.

2. Keeley D, McKean M (2006). Asthma and other wheezing disorders in children, search date October 2004. Online version of Clinical Evidence (15): 1–25.

3. National Institutes of Health (2002). National Asthma Education and Prevention Program Expert Panel Report: Guidelines for the Diagnosis and Management of Asthma—Update on Selected Topics 2002. Clinical Practice Guidelines (NIH Publication No. 02–5075). Bethesda, MD: U.S. Department of Health and Human Services.

Author:	Maria G. Essig, MS, ELS	Last Updated: May 15, 2007
Medical Review:	Caroline S. Rhoads, MD - Internal Medicine Harold S. Nelson, MD - Allergy and Immunology
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