Leukotriene Modifiers

Leukotriene modifiers, also called leukotriene receptor antagonists, are a group of medications. They can help prevent breathing problems associated with allergies, asthma and chronic obstructive pulmonary disease. Examples include montelukast, zafirlukast and zileuton.

What are leukotrienes?

Leukotrienes are chemicals your body releases (for example, when you come into contact with something you’re allergic to). They can cause:

  • Coughing.
  • Extra mucus and fluid in your chest and throat.
  • Inflammation or swelling in your airway.
  • Tight muscles in your airway.
  • Tightness in your chest.
  • Wheezing or difficulty breathing.


Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

What are leukotriene modifiers and what do they treat?

Leukotriene modifiers, also called leukotriene receptor antagonists or leukotriene synthesis inhibitors, are medications that block the effect of leukotrienes or stop your body from producing them.

These drugs are used to prevent or lessen the symptoms of:

What are the types of leukotriene modifiers?

Names of specific leukotriene modifiers include:

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

All three are used to treat asthma, but only montelukast is approved to treat allergic rhinitis.


How do leukotriene modifiers work?

Montelukast and zafirlukast are leukotriene receptor antagonists. They block the effects of leukotrienes.

Zileuton is a leukotriene synthesis inhibitor. It prevents the body from making leukotrienes.

How does someone take leukotriene receptor antagonists?

Leukotriene modifiers are taken orally (by mouth), usually a tablet.

They should be taken every day, whether you’re having trouble breathing or not. That’s because they’re used to help prevent breathing difficulty, not to treat an allergic reaction or asthma attack.

Your healthcare provider will give you specific instructions about:

  • Dose (how much to take and how often).
  • When to take the medication (for example, in the morning, twice a day).
  • Whether to take it with or without food.

Be careful not to take it more or less than what your healthcare provider prescribed.


What are the benefits of montelukast, zafirlukast and zileuton?

Leukotriene modifiers can help you:

  • Breathe more easily.
  • Exercise despite a breathing condition.
  • Keep your airway open.
  • Lessen mucous in your chest and throat.
  • Prevent breathing trouble, such as allergic reactions and asthma attacks.
  • Reduce the number and severity of reactions and attacks.

What are the risks of leukotriene modifiers?

Some leukotriene modifiers can cause liver damage. If you already have liver problems, you may not be able to take these medications. Your healthcare provider may order blood tests when you’re taking a leukotriene modifier to make sure your liver is safe.

What are the possible side effects of leukotriene modifiers?

Leukotriene modifiers are generally safe, but they can cause side effects, including:

  • Cold symptoms, such as cough, sore throat or runny nose.
  • Diarrhea.
  • Ear infection.
  • Fatigue (tiredness).
  • Flu-like symptoms, such as fever.
  • Headache.
  • Heartburn.
  • Itchy skin or rash.
  • Lack of appetite.
  • Nausea.
  • Stomach pain.

If you experience any serious side effects of leukotriene modifiers, call a healthcare provider or seek immediate medical attention. Severe side effects may include:

Change in mental health, such as depression, thoughts of suicide or sudden aggressiveness.

  • Hives, or skin that blisters or peels.
  • Hoarseness (sore throat or a raspy voice).
  • Heart palpitations.
  • Numbness or tingling in your hands or feet.
  • Swelling in your face, eyes, mouth or throat.
  • Trouble breathing or swallowing.
  • Vomiting.
  • Yellowing skin or eyes.

What interactions should I watch out for?

Leukotriene modifiers may interact with other medications, so it’s important to tell your healthcare provider about everything you take. The drugs might interact with:

  • Alpelisib, dabrafenib or enzalutamide (treatments for cancer).
  • Erythromycin and rifapentine (antibiotics that treat bacterial infections).
  • Loxapine (a drug to treat mental health conditions such as schizophrenia).
  • Lumacaftor (a treatment for cystic fibrosis).
  • Terfenadine (an antihistamine to prevent or treat allergy symptoms).
  • Warfarin (a blood thinner that can help prevent blood clots, strokes and heart attacks).

A note from Cleveland Clinic

Leukotriene modifiers, also called leukotriene receptor antagonists or leukotriene synthesis inhibitors, can help prevent breathing problems from allergies or asthma. They should be taken every day, whether or not you’re having breathing problems. Talk to your healthcare provider to see whether leukotriene modifiers are right for you.

Medically Reviewed

Last reviewed on 06/02/2021.

Learn more about our editorial process.

Appointments 216.444.6503