Leukotriene modifiers are medications that treat asthma and allergies. They work by blocking leukotrienes — chemicals that cause inflammation, airway narrowing and mucus — from working, or by preventing your body from making them. Montelukast, zafirlukast and zileuton are examples of leukotriene modifiers.
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Leukotriene modifiers, also called leukotriene receptor antagonists or leukotriene synthesis inhibitors, are medications used to treat asthma and allergies. They block the effect of leukotrienes (chemicals released by your immune system) or stop your body from producing them.
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Some medications, like rescue inhalers, treat symptoms once they start. But you take leukotriene modifiers daily to prevent asthma and allergy symptoms before they can cause a problem.
Serious side effects of leukotriene modifiers may include mental changes, like depression, thoughts of suicide and sleep disturbances.
If you have suicidal thoughts or behavior, call the healthcare provider who prescribed the medication immediately and get emergency medical attention. You can also call or text 988 in the U.S. to reach the Suicide and Crisis Lifeline. Someone is available to help you 24/7. If you’re in immediate danger, call 911 or your local emergency services number.
Leukotrienes are chemicals that are part of your immune system. They help your body generate an immune response to help protect it from things that could harm it.
Immune cells release leukotrienes in response to certain triggers, like allergens or exercise. Then, the leukotrienes latch onto (bind) receptors in your airways — similar to a key opening a lock — which causes inflammation.
The inflammation caused by leukotrienes can create mucus, narrow your airways (bronchoconstriction) and allow fluid to leak from your blood vessels. This can lead to asthma and allergy symptoms, like coughing and shortness of breath.
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Leukotriene modifiers work by either blocking leukotrienes or preventing your body from producing them. There are two types of leukotriene modifiers:
Montelukast (Singulair®) and Zafirlukast (Accolate®) are examples of leukotriene receptor antagonists. Zileuton (Zyflo®) is an example of a leukotriene synthesis inhibitor.
Leukotriene modifiers can prevent or lessen the symptoms of:
Leukotriene modifiers usually come in a tablet that you take by mouth (orally). You take them every day, whether you’re having symptoms or not. They aren’t used to treat acute asthma attacks.
Your healthcare provider will give you specific instructions about:
Tell your provider if you’re pregnant or might be pregnant. They might have you wait to start new medications. Most people who are already taking a leukotriene modifier while pregnant can keep taking it.
Always ask your provider if you have any concerns about medications you’re taking. Take all medications as prescribed.
Leukotriene modifiers can help you:
Rare risks of leukotriene modifiers include:
Your healthcare provider may order blood tests to check for these conditions while you’re taking a leukotriene modifier. If you have a condition that affects your liver health, you might not be able to take leukotriene synthesis inhibitors.
Side effects of leukotriene modifiers may include:
Call a healthcare provider or seek immediate medical attention if you experience any of these severe side effects:
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Leukotriene modifiers may interact with other medications, so it’s important to tell your healthcare provider about everything you take. The medications might interact with:
It can take several weeks of taking leukotriene modifiers daily before you notice a difference in symptoms.
Talk to your healthcare provider if you:
Call 911 (or your local emergency services number) or go to the nearest emergency room if you experience severe side effects, especially mental changes like suicidal thoughts.
Asthma and allergies can make you change the way you live your life. You might find yourself avoiding things you once enjoyed, like spending time outside, physical activities or exercising. For some people, leukotriene modifiers have helped allow them do more of what they love and improve their quality of life.
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But like any medications, they’re not without risk. Talk to your provider if you’re wondering if leukotriene modifiers are right for you. Let them know about other medications you’re taking, medical conditions you have or if you’re pregnant. And always let them know right away if you experience side effects.
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Cleveland Clinic’s health articles are based on evidence-backed information and review by medical professionals to ensure accuracy, reliability and up-to-date clinical standards.
Cleveland Clinic’s health articles are based on evidence-backed information and review by medical professionals to ensure accuracy, reliability and up-to-date clinical standards.
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