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Montelukast (Singulair): Your Most Common Questions Answered

Answers to Your Most Common Questions About Montelukast

Montelukast is a drug used in the long-term treatment of asthma. It may also be used acutely to prevent asthma symptoms brought on by exercise (called exercise-induced asthma or exercise-induced bronchoconstriction) or to relieve symptoms of allergic rhinitis (hay fever).

Here are the answers to 10 of the most frequently asked questions about montelukast.

The content on this page is provided for informational purposes only. If you have any questions or concerns about your treatment, you should talk to your doctor, pharmacist, or healthcare professional. This is particularly important if you are taking multiple medications or have any existing medical conditions.

  1. What is montelukast?
  2. What is montelukast sodium?
  3. What is montelukast used for?
  4. Why do you have to take montelukast at night?
  5. How long does it take montelukast to work?
  6. What are the side effects of montelukast?
  7. How long does montelukast stay in your system?
  8. Do other drugs interact with montelukast?
  9. Can I take montelukast while pregnant?
  10. Can I drink alcohol while taking montelukast?

1. What is montelukast?

Montelukast is a popular medication for treating asthma and allergies. It is taken orally in the form of tablets, chewable tablets, or granules. It is sold under the brand name Singulair, among others, and is available as a generic medication.

Montelukast falls under a class of drugs called leukotriene receptor antagonists, which also includes zafirlukast and pranlukast. Leukotrienes are enzymes released by the immune system that promote inflammation and bronchoconstriction (the narrowing of your airways). Drugs such as montelukast work by preventing specific leukotriene receptors from functioning and, therefore, reducing the inflammatory response and helping prevent bronchoconstriction.

By blocking leukotriene receptors, montelukast also helps prevent mucus secretion and airway edema (or oedema), which is swelling caused by excess fluid in your body’s tissue.

2. What is montelukast sodium?

Montelukast and montelukast sodium are the same drug. Medications are often converted into salt form to improve their solubility in water, which quickens absorption into the bloodstream and improved their therapeutic effect.

“Sodium” refers to the chemical makeup of montelukast in its salt form but is often dropped from the name for convenience.

3. What is montelukast used for?

Asthma

Leukotriene receptor antagonists, such as montelukast, are not typically used as first-line treatments for asthma. Rather, they tend to be used in addition to inhaled corticosteroids such as fluticasone and budesonide.

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Montelukast, as described above, works by blocking leukotrienes and reducing inflammation, bronchoconstriction, mucus secretion, and edema. This mechanism of action helps prevent typical asthma symptoms, including wheezing, chest tightness, and breathing difficulties. It also helps prevent asthma attacks. However, it is not used as emergency/rescue medicine should an asthma attack occur.

It can be used by adults and children as young as 12 months old. Montelukast is usually administered once per day in the following forms and strengths:

  • Tablet (10-mg) form for adults and children 15 years of age or above
  • Chewable tablet (5-mg) form for children between 6 and 14 years of age
  • Chewable tablet or granule form (4-mg) for children between 2 and 5 years of age
  • Granule form (4-mg) for children between 12 and 23 months old

The dosages and forms quoted are those recommended by the FDA.

Exercise-induced asthma

Montelukast may also be used acutely to prevent exercise-induced asthma (or exercise-induced bronchoconstriction) in adults and children 6 years of age and above.

The FDA recommends 5-mg chewable tablets for children between 6 and 14 years of age, and 10-mg tablets for adults and adolescents 15 years of age and above.

It is usually recommended that montelukast is taken at least two hours before undertaking exercise, to prevent symptoms such as wheezing, coughing, and tightness in your chest. Montelukast should not be taken more than once every 24 hours.

Allergic rhinitis (hay fever)

First-line treatments for allergic rhinitis, which is commonly called hay fever, are usually:

  • Intranasal corticosteroids, including fluticasone and budesonide (which are inhaled in asthma treatment)
  • Antihistamines (such as cetirizine, loratadine, and fexofenadine)
  • A combination of both an intranasal corticosteroid and an antihistamine

However, montelukast can also be used to prevent the typical symptoms of allergic rhinitis, such as sneezing, stuffy nose, runny nose, and itching of the nose. It can be used both seasonal and perennial (year-round) allergic rhinitis.

For both seasonal and perennial allergic rhinitis, montelukast is usually prescribed once daily in the following forms and strength:

  • Tablet (10-mg) form for adults and children 15 years of age or above
  • Chewable tablet (5-mg) form for children between 6 and 14 years of age
  • Chewable tablet or granule form (4-mg) for children between 2 and 5 years of age

Montelukast granules (4-mg) may also be prescribed once daily to treat perennial allergic rhinitis in children between 6 and 23 months old.

The dosages, forms, and ages quoted are those recommended by the FDA. Recommendations from other health authorities may vary. If you have any questions or concerns regarding your or your child’s treatment, you should speak to your doctor.

4. Why do you have to take montelukast at night?

The recommended time for taking montelukast varies depending on the condition it is being used to treat.

When montelukast is used to treat exercise-induced asthma, it is recommended that you take it at least two hours before exercising (and not within 24 hours of a previous dose). This can be at any time throughout the day.

When montelukast is used to treat asthma, it is recommended that you take it in the evening. The FDA says that although there is no evidence that montelukast is more effective when taken in the evening than in the morning, trials demonstrating its efficacy have all been conducted with evening doses. Basically, the advice for taking montelukast in the evening is due to a lack of evidence that it is effective when taken in the morning.

When montelukast is used to treat allergic rhinitis, it is usually recommended that it is taken at the same time each day. However, this can be at any time during the day.

In any case, montelukast can be taken without regard to when you eat.

If you have any questions or concerns regarding the time at which you or your child takes montelukast, you should speak to your doctor.

5. How long does it take montelukast to work?

Clinical trials have found montelukast to have an effect within 24 hours of the first dose in the treatment of asthma and allergic rhinitis. Montelukast has been found to offer protection from the symptoms of exercise-induced asthma after two hours.

Despite the relatively quick onset of action, montelukast does not work fast enough to treat an asthma attack and should not be used as an emergency/rescue medicine.

6. What are the side effects of montelukast?

Like any drug, montelukast can cause side effects. Some of the more common side effects include:

  • Headache
  • Stomach pain or discomfort
  • Diarrhea
  • Heartburn
  • Tiredness
  • Sore throat
  • Tooth pain

You should speak to your doctor if any of these side effects are serious, don’t go away, or get worse.

More serious side effects are uncommon but can occur. You should speak to your doctor immediately if you notice any of the following side effects:

  • Mood or behavioral changes, including depression, anxiety, aggression, thoughts of self-harm or suicide, disturbing dreams, or hallucinations
  • Numbness, tingling, shooting pain or pins and needles in your arms or legs
  • Pain, irritation, or swelling of your sinuses

Allergic reactions to montelukast are rare but can occur. Signs of a serious allergic reaction should be treated as a medical emergency. They include:

  • Skin rash – for example itchy, red, or swollen skin
  • Wheezing
  • Tightness in the chest or throat
  • Trouble breathing or talking
  • Swollen mouth, face, lips, tongue, or throat

This is not an extensive list of possible side effects of montelukast. For more information about side effects, please read the information leaflet that comes with the medication or speak to your doctor or pharmacist.

7. How long does montelukast stay in your system?

The half-life of a drug refers to the time it takes for 50% of the drug to be eliminated from the body. With each subsequent half-life, a further 50% of the remaining drug is eliminated.

The average half-life of montelukast is between 2.7 and 5.5 hours. It takes approximately 5.5 x the half-life of a drug for it to be cleared from your system, meaning montelukast stays in your system for between roughly 15 and 30 hours.

8. Do other drugs interact with montelukast?

Montelukast has not been found to cause adverse reactions with other drugs, nor has it been found to have a clinically important effect on the concentration of other drugs in your bloodstream.

Nonetheless, you should always speak to your doctor about every medication and supplement you take.

9. Can I take montelukast while pregnant?

Animal studies have not found montelukast to harm a developing fetus. However, there is no adequate evidence regarding the safety of montelukast during human pregnancy.

The FDA does note that there are rare reports of congenital limb defects in children of women taking montelukast, but that most were also taking other medications and no definitive link has been established. Based on all the available evidence, the FDA classes montelukast in Pregnancy Category B, meaning it is considered safe to use during pregnancy if there is a clinical need.

Montelukast has been shown to pass into breast milk in animal studies but it is not known whether it is excreted in human breast milk.

If you are pregnant, planning on getting pregnant, or are a nursing mother, you should speak to your doctor about montelukast and any other medications you are taking.

10. Can I drink alcohol while taking montelukast?

Montelukast has not been found to directly interact with alcohol. However, if you are experiencing side effects such as drowsiness or dizziness, alcohol could make these side effects worse.

If you wish to consume alcohol while taking montelukast, you should discuss the safest way of doing so with your doctor.


The content on this page is provided for informational purposes only. If you have any questions or concerns about your treatment, you should talk to your doctor, pharmacist, or healthcare professional. This is particularly important if you are taking multiple medications or have any existing medical conditions.

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