Singulair dosage, forms, and strengths

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The dosages listed are general guidelines; your healthcare provider may adjust your dose based on individual health factors.

Singulair (montelukast sodium) is a brand-name prescription medication that controls allergy and asthma symptoms in adults and children. The FDA has approved Singulair specifically as a maintenance treatment for asthma, symptom relief of allergic rhinitis, and prevention of exercise-induced asthma. 

RELATED: What is Singulair? | Singulair side effects

Singulair dosage for asthma

The FDA has approved Singulair as a long-term treatment of asthma in adults and children 12 months of age and older. Montelukast works by inhibiting the action of leukotrienes in the body. These molecules cause swelling, mucus buildup, airway constriction, and other allergy symptoms when the body senses a foreign substance such as an allergen. For asthma, montelukast minimizes swelling and airway constriction caused by allergens. Doses are taken once daily. The best time to take Singulair for asthma is in the evening.

Singulair dosage for hay fever

Singulair is also FDA-approved to relieve symptoms in both seasonal and perennial allergic rhinitis (hay fever) in adults and children. For seasonal allergic rhinitis, Singulair can be used in patients 2 years and older, and for perennial allergic rhinitis, Singulair can be used in patients six months and older. For allergies, Singulair is typically used when other treatments have not worked or cannot be tolerated. Doses are taken once daily, at any time of day.

Singulair dosage for exercise-induced bronchoconstriction

Exercise-induced bronchoconstriction (EIB) is a condition in which airways narrow during or after exercise. About 40% to 90% of people with asthma have EIB, but people without asthma can also have the problem. Singulair can be used in adults and children as young as 6 years with EIB. A single dose is taken at least two hours before exercise.

Personalized dosing considerations

Dosage adjustment is not required or recommended for people with kidney disease, liver disease, or other health conditions.

Singulair safety info

Singulair is not a rescue inhaler and does not help relieve the active symptoms of an asthma attack. People taking Singulair for asthma or exercise-induced bronchoconstriction should always carry a rescue inhaler with them in case of a sudden asthma attack.

Singulair is a safe medication for most people to take, though infections and upper respiratory tract complaints are common side effects. The only people who should never take Singulair are those who have had an allergic reaction to this drug. 

People with phenylketonuria (PKU) should know that the Singulair chewable tablets contain aspartame (a source of phenylalanine), which can cause harm. Those with PKU who need to take Singulair may be prescribed a different formulation.

The most worrisome problems associated with Singulair therapy are neuropsychiatric and behavioral problems, including depression, suicidal thoughts, hostility, tics, sleep disturbances, hallucinations, aggression, and seizures. Make sure the prescriber knows if you have a history of mental health conditions or behavioral problems. Stop taking Singulair and immediately contact the prescriber if you or your child experiences any significant changes in mood or behavior. For emergencies, you can call 911. For suicidal thoughts or crises, you can call or text 988 for the Suicide & Crisis Lifeline.

Check with your healthcare provider if you are pregnant, planning to become pregnant, or breastfeeding. 

Before you or your child take Singulair, tell the healthcare provider about any allergies to medicine, including aspirin. Be sure to tell the provider about all the medicines you or your child take, including prescription and OTC drugs, vitamins, and supplements.

Drinking alcohol is not prohibited, but talk to the healthcare provider first.

How to take Singulair

Only one dose of Singulair is taken daily. It comes in three different dosage formats, each with different directions.

• Follow all the prescriber’s instructions.

• Do not take more than one dose daily.

• For asthma, take the daily dose in the evening.

• For hay fever, the daily dose can be taken at any time of day.

• For exercise-induced bronchoconstriction, take a dose at least two hours before exercise. Do not take more than one dose daily.

• Singulair can be taken with or without food.

• Do not give chewable tablets to children younger than 2 years of age.

• Read the Instructions for Use before giving a child Singulair oral granules.

  • Oral granules can be poured directly into the child’s mouth, dissolved in one teaspoon of room temperature baby formula or breast milk, or mixed with mashed carrots, applesauce, mashed rice, or ice cream.

  • If Singulair granules are mixed with water, formula, or food, give the mixture to the child within 15 minutes.

• Store Singulair tablets, chewable tablets, or oral granules at room temperature protected from light and moisture. Keep out of reach of children and pets.

Singulair dosage FAQs

How long does it take Singulair to work?

Singulair begins working quickly. Most people will feel the effects of a dose within a few hours. It may take one to two weeks to feel the full effects of treatment.

What happens if I miss a dose of Singulair?

If you miss a dose of Singulair, skip the missed dose and take the next dose at its regular time. Never take more than one dose at the same time.

How long can you take Singulair?

Singulair is typically prescribed as a long-term maintenance medication. The length of time you take Singulair will depend on your condition and how you respond to treatment. 

How do I stop taking Singulair?

Singulair can be stopped without causing withdrawal symptoms, but symptoms might worsen. Consult with the prescriber before stopping this drug in case an alternative treatment is needed.

Is it best to take Singulair at night?

When used to treat asthma, Singulair should be taken at night. For hay fever, Singulair can be taken at any time of day. For exercise-induced bronchoconstriction, take the Singulair dose at least two hours before exercising.

Sources:

• Exercise-induced bronchoconstriction, StatPearls (2025)

• Montelukast, StatPearls (2023)

• Singulair, Prescriber’s Digital Reference (PDR)

• Singulair, DailyMed (2025)