Known brand names include Singulair.
A once-daily oral leukotriene blocker. It is used for long-term asthma control, to prevent exercise-induced bronchoconstriction, and for allergic rhinitis when other treatments fail or are not tolerated. It does not treat an acute asthma attack.
Montelukast blocks the CysLT1 receptor, a receptor in the airways that responds to chemicals called leukotrienes. Certain cells, including mast cells and eosinophils, release leukotrienes during asthma and allergic reactions. In asthma they make the airway lining swell, tighten the airway muscle, and feed inflammation, and in allergies they are released in the nose after contact with an allergen. By blocking the receptor without switching it on, it keeps leukotrienes from causing these effects.
Taken by mouth, it is absorbed quickly and reaches its peak blood level within a few hours. In studies it blunted both the early and the later airway tightening that follows breathing in an allergen. It does not reverse airway tightening during a sudden attack, though it can be continued through an asthma flare. The label says the cause of its mood and behavior side effects is not well understood.
Montelukast is a medicine taken by mouth for long-term asthma control, to prevent wheezing, chest tightness, coughing, and trouble breathing. It also helps prevent the airway tightening that exercise can bring on. It eases the sneezing and the stuffy, runny, or itchy nose of allergic rhinitis, both the seasonal kind and the kind that lasts all year.
Children can take it for asthma from 12 months of age, for exercise-related airway tightening from 6 years, for year-round allergies from 6 months, and for seasonal allergies from 2 years. It comes as tablets, chewable tablets, and granules, and people with asthma keep using their other asthma medicines alongside it. For allergies, it is kept for people who did not do well with other treatments or could not tolerate them, because of its risk of mood and behavior changes. It does not treat a sudden asthma attack, which needs a fast-acting rescue inhaler.
Headache, cold symptoms, sore throat, cough, stomach upset, and diarrhea are the common complaints, and children may get fevers, flu, and ear or sinus infections. The label treats mood and behavior changes as the most serious risk, including agitation, aggression, depression, strange dreams, trouble sleeping, hallucinations, and suicidal thoughts. It also warns about a rare inflammation of blood vessels, sometimes as steroid pills are tapered.
A clinician may order these while someone is taking it.
Sources: [1]
This is the boxed warning, the warning the FDA label prints first.
Serious neuropsychiatric events, including agitation, aggression, depression, sleep disturbances, and suicidal thoughts and behavior, including suicide. Benefits may not outweigh risks when symptoms are mild; reserve for allergic rhinitis that has not responded to or tolerated other therapies. Teach patients and caregivers to watch for behavior changes and to stop the drug and call a provider right away if they occur.
Sources: [1]