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.
Labeled use. Single dose before exercise, from 6 years of age.
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Labeled use. Prophylaxis and chronic treatment from 12 months of age; not for acute attacks.
Labeled use. Reserve for inadequate response or intolerance to other therapies because of neuropsychiatric risk.
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Inhaled corticosteroids are preferred over montelukast for persistent asthma; montelukast is an alternative or add-on when inhalers cannot be used or are refused, and is convenient for young children or aspirin-exacerbated respiratory disease. For allergic rhinitis, intranasal steroids and antihistamines come first because of the boxed neuropsychiatric warning. It can be used before exercise, but a short-acting beta-agonist works faster.
Binds selectively to the cysteinyl leukotriene type 1 (CysLT1) receptor in the airways and on inflammatory cells and blocks leukotriene D4, with no agonist activity. This reduces leukotriene-driven airway edema, smooth muscle contraction, and inflammation in asthma and allergic rhinitis. It is metabolized mainly by CYP2C8, with CYP3A4 and 2C9.
The label does not describe a narrow therapeutic index or direct dosing by measured blood levels of the drug.
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Doses come from the FDA label. Study tool, not for clinical decisions.
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]
No specific antidote. Use usual supportive measures, such as removing unabsorbed drug, clinical monitoring, and supportive therapy. Whether dialysis removes montelukast is unknown.
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Decades of cohort studies have not shown a link to major birth defects, though the studies have limitations. Poorly controlled asthma in pregnancy raises the risk of preeclampsia, prematurity, and low birth weight.
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Present in human milk. Available data do not suggest a significant risk to the breastfed infant; effects on milk production are unknown.
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Ages 6 to 14: 5 mg chewable tablet. Ages 2 to 5: 4 mg chewable tablet or 4 mg granules. Asthma from 12 months, and perennial allergic rhinitis from 6 months, to 23 months: 4 mg granules. All once daily. For exercise prevention, use only from age 6. Neuropsychiatric events have occurred in children.
No overall differences in safety or effectiveness. Half-life is slightly longer in older adults, but no dose change is needed.
Sources: [1]