Leukotriene Antagonists

What do these medicines do?

Leukotrienes are chemicals produced by the body that cause the smooth muscles of the airways to narrow, making it harder to breathe. Leukotrienes also lead to swelling and irritation of the lining of the airway. Leukotriene antagonists block the production or the effects of leukotrienes. They reduce swelling, inflammation and mucus production in the airways. This helps prevent asthma symptoms. These medicines are not quick-acting bronchodilators and are not helpful in the treatment of asthma attacks. They are used long-term to help prevent asthma attacks. They may also help control allergic nasal symptoms.

What are other names for these medicines?

Examples of this medicine are montelukast (Singulair), zafirlukast (Accolate) and zileuton (Zyflo). Montelukast has been approved for use in children over 1 year of age. Zafirlukast is approved for use in children 5 years of age and older. Zileuton is approved for use in children 12 years of age and older.

How are they taken?

Singulair comes as a coated tablet, a chewable tablet, and as oral granules. Accolate and Zyflo are available in tablet form.

What is the usual dose?

Montelukast comes in 3 strengths (4 mg, 5 mg, and 10 mg) and is taken once daily. Zafirlukast comes in 2 strengths ( 10 mg, 20 mg) and is taken twice daily, one hour before a meal or 2 hours after a meal. Zileuton comes in one strength (600 mg) and is taken 4 times a day.

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What side effects can these drugs cause?

Side effects with the use of montelukast are rare. The most common side effects include headache and nausea. Zafirlukast and zileuton may cause liver problems. If your child is taking these medicines and has pain in the upper right side of the abdomen, nausea, fatigue, itching, or flu-like symptoms that won't go away, call your child's health care provider right away. These could be signs of liver problems. Children who take zileuton must have blood tests regularly to check for liver damage.

What special instructions should be followed?

To prevent symptoms of asthma, children should take their leukotriene antagonist exactly as prescribed by their health care provider. These medicines should be taken regularly on a daily basis and not stopped unless told to do so by the health care provider. Children taking zafirlukast should take the medicine 1 hour before or 2 hours after meals.