Leukotriene Receptor Antagonists (LTRAs)

Reviewed by: HU Medical Review Board | Last Reviewed: September 2022 | Last updated: November 2022

Leukotriene receptor antagonists (LTRAs) are prescription drugs used to treat asthma. They work by blocking the actions of chemicals in the body called leukotrienes.1-3

LTRAs relieve nasal and sinus congestion caused by hay fever, seasonal allergies, and year-round (chronic) allergies. While useful to some people, studies show these drugs tend to be less effective than nasal corticosteroids.3

How do LTRAs work?

Leukotrienes are chemicals in the body. When released in reaction to an allergen, leukotrienes cause lung inflammation, extra mucus, and tightening of the airways. This leads to shortness of breath, wheezing, coughing, and post nasal drip.1,3

Leukotriene inhibitors help make it easier to breathe by preventing the action of leukotrienes. They help to reduce airway narrowing and inflammation in the lungs.1,3

Examples of LTRAs

There are 2 types of LTRAs, but only 1 is approved to treat allergies. This drug is Singulair® (montelukast sodium).1-4

Singulair is available by prescription as a chewable tablet, granules, or tablet. It comes in different strengths and is prescribed based on age. Some forms are approved for use in children as young as 6 months old.1-4

What are the possible side effects?

The most common side effects of Singulair include:1,4

  • Upper respiratory tract infection
  • Fever
  • Headache
  • Sore throat
  • Cough
  • Stomach pain
  • Ear infection or ear ache
  • Diarrhea
  • Flu
  • Runny nose
  • Sinus infection

Call your doctor right away if you have 1 or more of these symptoms:1,4

  • Rash
  • Flu-like symptoms
  • Pins and needles or numbness in the arms or legs
  • Severe pain and swelling of the sinuses

Singulair has a boxed warning, the strictest warning from the U.S. Food and Drug Administration (FDA). It has this warning because severe mental health problems have happened in people while taking this drug or even after stopping Singulair. These issues include:1,4

  • Aggressive behavior
  • Problems paying attention
  • Unusual dreams, sleepwalking, trouble sleeping
  • Depression
  • Memory loss, forgetfulness, confusion
  • Agitation, anxiety, irritability
  • Hallucinations
  • Uncontrollable repeating thoughts
  • Restlessness
  • Stuttering, uncontrolled muscle movements
  • Thoughts or acts of self-harm

Stop taking Singulair right away and call your doctor if you or your child have any unusual changes in behavior or thinking.1,4

These are not all the possible side effects of Singulair. Talk to your doctor about what to expect when taking Singulair. You also should call your doctor if you have any changes that concern you when taking Singulair.

Other things to know

For the treatment of allergies, the FDA recommends that Singulair not be the first choice treatment for allergies. It should be reserved for those who have not responded well to other treatments.1,4

If you have asthma and aspirin makes your asthma symptoms worse, you should avoid aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs) while taking Singulair.4

Before taking Singulair, tell your doctor if you:1,4

  • Are allergic to aspirin
  • Have phenylketonuria
  • Have or have had mental health issues
  • Are pregnant or planning to become pregnant
  • Are breastfeeding or planning to breastfeed

Before beginning treatment for allergies, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you take. This includes over-the-counter drugs.

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