Trade name Singulair

A leukotriene receptor antagonist (LTRA) used for the maintenance treatment of asthma and to relieve symptoms of seasonal allergies.


It blocks the action of leukotriene D4 and secondary ligands LTC4 and LTE4 on the cysteinyl leukotriene receptor CysLT1 in the lungs and bronchial tubes by binding to it.



Reduces the bronchoconstriction otherwise caused by the leukotriene and results in less inflammation.


Not useful for the treatment of acute asthma attacks, it does not interact with other asthma medications as it has a very specific mechanism of action.



Used for asthma, exercise induced bronchospasm, allergic rhinitis, and urticaria.


It is mainly used in adults in addition to inhaled corticosteroids to bring the desired effect.


Supplied as a tablet, a chewable tablet, and granules to take by mouth.


Usually taken once a day with or without food.


Administered as montelukast sodium, with 5.2 mg of montelukast sodium being equivalent to 5 mg of montelukast.

Montelukast is usually taken once a day with or without food.

Pregnancy category B.

Bioavailability 63–73%.




Hepatic metabolism with CYP3A4 and CYP2C9 activity.




Has biliary excretion.


Protein binding 99%.

Biological half-life 2.7–5.5 hours.

Excretion is biliary

It is not useful in the treatment of acute asthma attacks.

Used for asthma, exercise induced bronchospasm, allergic rhinitis, primary dysmenorrhoea and urticaria.

It is mainly used as a complementary therapy in adults in addition to inhaled corticosteroids,

Side effects include: diarrhea, nausea, vomiting, mild rashes, asymptomatic elevations in liver enzymes, fever, headaches, drowsiness, hypersensitivity reactions, sleep disorders, and bleeding tendency.

Use is associated with a higher incidence of Churg–Strauss syndrome.


Increased risk of insomnia, suicidal behavior, agitation, aggression, anxiousness, dream abnormalities, hallucinations, depression, irritability, restlessness, and tremor.

Uncommon side effects include: fatigue and malaise, behavioral changes, paresthesias and seizures, muscle cramps, and nose bleeds.

Rare side effects include severe behavioral changes, angioedema, erythema multiforme, and liver problems.

Has very few drug-drug interactions.

It is an inhibitor of the drug metabolizing enzyme CYP2C8.

The usual dose in adults and teenagers is one 10 mg tablet taken orally a day.

In children 6 to 14 years of age the usual dosage is one 5 mg chewable tablet a day, and in children 6 months to 6 years old 4 mg granules once daily

Reduces infusion reactions of Daratumumab.


The FDA now requires a boxed warning for montelukast due to the risk of neuropsychiatric events associated with the drug.


Associated with a risk of severe mental health side effects, including thoughts of suicide.


Symptoms can include bad or vivid dreams, depression, disorientation or confusion, feeling anxious, hallucinations, irritability, restlessness, stuttering, and uncontrolled muscle movements.



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