What Is Montelukast? Uses, Dosage, and What You Need to Know in 2026

Montelukast is one of the most widely prescribed medications in the United States, used by millions of patients each year for asthma and allergies. If you've been prescribed montelukast — or you're wondering whether it's right for you — this complete guide covers everything you need to know: what it is, what it treats, how to take it, and key safety information.

What Is Montelukast?

Montelukast is a prescription medication in the drug class known as leukotriene receptor antagonists (LTRAs). It is the generic name for the brand-name drug Singulair, which was originally manufactured by Merck. The brand-name patent expired in August 2012, and generic versions have been widely available ever since.

Montelukast works by blocking leukotrienes — inflammatory chemicals released by the body in response to allergens, exercise, and other triggers — that cause airway swelling, mucus production, and narrowing of the airways. By blocking these chemicals, montelukast helps prevent asthma attacks and reduce allergy symptoms.

What Is Montelukast Used For?

Montelukast was first FDA-approved in 1998. It is FDA-approved for:

Chronic asthma treatment and prevention in adults and children 12 months and older. It is a controller (maintenance) medication — it prevents asthma attacks but does not stop an attack that has already started.

Exercise-induced bronchoconstriction (EIB) prevention in patients 6 years and older. A single dose taken at least 2 hours before exercise can prevent the airway narrowing that some people experience during physical activity.

Seasonal allergic rhinitis (hay fever) in patients 2 years and older. Relieves sneezing, runny nose, nasal congestion, and itchy eyes caused by seasonal outdoor allergens like pollen.

Perennial allergic rhinitis (year-round allergies) in patients 6 months and older. Treats symptoms caused by year-round indoor allergens like dust mites, pet dander, and mold.

Montelukast is also used off-label for chronic hives (urticaria) and certain other allergic conditions, though these uses are not formally FDA-approved.

What Forms Does Montelukast Come In?

10 mg film-coated tablet: For adults and adolescents 15 years and older. Swallow whole with water.

5 mg chewable tablet: For children 6–14 years. Must be chewed before swallowing. Contains aspartame — not appropriate for patients with PKU.

4 mg chewable tablet: For children 2–5 years. Must be chewed before swallowing. Contains aspartame.

4 mg oral granule packet: For infants and young toddlers starting at 6 months. Can be swallowed directly, dissolved in baby formula or breast milk, or mixed with a soft food like applesauce or mashed carrots. Must be given within 15 minutes of opening.

Montelukast Dosage by Age and Indication

Montelukast is taken once daily for asthma and allergic rhinitis. The dosing schedule varies slightly based on indication and age:

Adults and teens 15+ (asthma): 10 mg once daily in the evening

Children 6–14 years (asthma): 5 mg chewable tablet once daily in the evening

Children 2–5 years (asthma): 4 mg chewable tablet or 4 mg granule packet once daily in the evening

Infants 12–23 months (asthma): 4 mg oral granule packet once daily in the evening

EIB prevention (6+ years): Single dose at least 2 hours before exercise; do not take an additional dose within 24 hours

Seasonal allergic rhinitis (15+): 10 mg once daily; timing flexible

How to Take Montelukast

Montelukast can be taken with or without food.

For asthma, take in the evening — asthma symptoms and airway swelling typically worsen at night.

For allergic rhinitis only, timing is flexible — you can take it morning or evening.

Montelukast is NOT a rescue inhaler. Do not use it for a sudden asthma attack. Always keep a short-acting rescue inhaler (albuterol) available.

Continue taking montelukast every day, even when you feel well. It is a maintenance medication that works best when taken consistently.

Key Safety Information

Black box warning: Montelukast carries the FDA's highest warning level for serious neuropsychiatric side effects including depression, suicidal thoughts, aggression, and behavioral changes. Stop and call your doctor if these occur.

Not a controlled substance: Montelukast is not a scheduled substance and has no abuse potential.

Safe in pregnancy: Available evidence does not establish a drug-associated risk of major birth defects. Discuss with your OB if you're pregnant.

Curious about how montelukast works at a deeper level? Read our guide: How Does Montelukast Work? If you need help finding it at a pharmacy near you, medfinder can search for you.