Leukotriene pathway modifiers for long-term control of asthma


Generic Name Brand Name
montelukast Singulair
zafirlukast Accolate
zileuton Zyflo

These medications are available as pills and chewable tablets.

How It Works

Leukotriene pathway modifiers improve lung function and decrease asthma symptoms.

Why It Is Used

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. Medication treatment for asthma depends on a person’s age, his or her type of asthma, and how well the treatment is controlling asthma symptoms.

  • Children up to age 4 are usually treated a little differently than those 5 to 11 years old.
  • The least amount of medicine that controls the asthma symptoms is used.
  • The amount of medicine and number of medicines are increased in steps. So if asthma is not controlled at a low dose of one controller medicine, the dose may be increased. Or another medicine may be added.
  • If the asthma has been under control for several months at a certain dose of medicine, the dose may be reduced. This can help find the least amount of medicine that will control the asthma.
  • Quick-relief medicine is used to treat asthma attacks. But if you or your child needs to use quick-relief medicine a lot, the amount and number of controller medicines may be changed.

Your doctor will work with you to help find the number and dose of medicines that work best.

How Well It Works

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

Side Effects

Leukotriene pathway modifiers sometimes cause side effects such as vomiting, diarrhea, and headaches. Rarely, they can cause more serious problems such as mood changes, depression, hallucinations, and suicidal thinking.

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.)

What To Think About

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. Preferred medicines are inhaled corticosteroids with or without 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 doctor 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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  1. Dennis RJ, et al. (2007). Asthma in adults, search date October 2006. Online version of BMJ Clinical Evidence: http://www.clinicalevidence.com.
  2. Keeley D, McKean M (2006). Asthma and other wheezing disorders in children, search date October 2005. Online version of BMJ Clinical Evidence: http://www.clinicalevidence.com.
  3. National Institutes of Health (2007). National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma (NIH Publication No. 08–5846). Available online: http://www.nhlbi.nih.gov/guidelines/asthma/asthgdln.htm.

Last Updated: April 21, 2009

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