Nursing care
Montelukast: what to check before you give it
Written and reviewed by Dana Whitfield, RN, MSN · 4 min read · Updated September 2026
Short answer
Montelukast is a leukotriene receptor antagonist taken once daily in the evening to prevent asthma and allergic rhinitis symptoms — it has no role in an acute attack. Patients need to understand it will not stop wheezing that has already started; a rescue inhaler is still required for breakthrough symptoms.
Why this drug and not another
Montelukast blocks leukotriene receptors in the airway, preventing the bronchoconstriction, mucus secretion, and inflammation that leukotrienes drive during an asthma or allergy response. It is chosen over an inhaled corticosteroid when a patient has exercise-induced bronchospasm, allergic rhinitis alongside asthma, or difficulty adhering to inhaler technique, since it comes as an oral tablet or chewable.
It is often added on to, not substituted for, inhaled therapy in moderate persistent asthma, giving control through a different pathway than corticosteroids or beta-agonists. Its oral route also makes it a practical option for children who struggle with inhaler coordination, and for patients whose asthma is closely tied to seasonal allergies.
Administration and timing
Montelukast is taken once daily in the evening, with or without food, and this timing is deliberate rather than a convenience note. Leukotriene levels and airway reactivity tend to rise overnight, so dosing in the evening lines the drug's peak effect up with the period of greatest risk for nocturnal symptoms.
It takes days of consistent dosing to build the preventive effect, so it is prescribed for maintenance, not for use as needed. Chewable tablets for children should not be swallowed whole without chewing, and granule formulations can be given directly in the mouth or mixed with a small amount of soft food, but never dissolved in liquid.
Monitoring parameters
Monitor for improvement in daytime and nighttime asthma symptoms, reduced use of rescue inhaler, and better peak flow readings over the first one to two weeks of therapy, since montelukast has no immediate measurable effect the way a bronchodilator does. There is no serum level to check, which is part of why it appeals as a lower-burden add-on therapy.
Screen for and document baseline mood and behavior, because neuropsychiatric changes are a recognised risk with this drug. Any new agitation, sleep disturbance, depression, or suicidal ideation after starting therapy should be tracked against that baseline and reported, particularly in adolescent and paediatric patients.
Adverse effects to report
The neuropsychiatric adverse effects carry a boxed warning and are the ones to escalate without delay: agitation, aggression, anxiety, abnormal dreams, depression, and suicidal thinking or behaviour. These can appear even in patients with no prior psychiatric history, and families should be told to watch for them, not just the patient.
Headache and GI upset are common and usually mild, not requiring the drug to be stopped. Report any signs suggestive of Churg-Strauss syndrome, a rare eosinophilic vasculitis associated with leukotriene antagonists, which can present as worsening pulmonary symptoms, rash, or new sinus disease, particularly if a patient's steroid dose is being tapered at the same time.
Contraindications and cautions
There are no major absolute contraindications, but montelukast should be used cautiously in patients with a history of mental health conditions given the neuropsychiatric risk, and the prescriber should weigh that history before starting therapy. Hepatic impairment warrants closer observation since the drug is metabolised by the liver.
It is not a substitute for corticosteroid therapy and should not be used to taper a patient off inhaled or oral steroids abruptly, since doing so can unmask an underlying condition or precipitate an asthma flare. It also carries no proven role as rescue therapy, and using it that way delays effective treatment during an acute episode.
Teaching points the exam tests
The single fact tested most often is that montelukast is for prevention and taken in the evening, and it does nothing for an attack that has already started. Patients must keep a rescue inhaler with them at all times and know to use that, not montelukast, for acute wheezing or shortness of breath.
Teach patients not to stop other asthma medications, including inhaled corticosteroids, without the prescriber's direction, even if montelukast seems to be working well. Tell them to report any mood or behaviour change promptly, and to take the dose consistently every evening rather than only on days with symptoms, since its benefit depends on steady daily use.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our respiratory practice questions are the closest set to what this page covers.
Common questions
Why is montelukast taken in the evening?
Leukotriene-driven airway reactivity tends to peak overnight, so an evening dose times the drug's effect to cover that period. It is a preventive schedule, not tied to meals or symptoms.
Can montelukast be used for an asthma attack?
No. It has no bronchodilator effect and will not relieve acute wheezing or shortness of breath. Patients need a rescue inhaler for breakthrough symptoms regardless of how consistently they take montelukast.
What mental health effects should nurses watch for with montelukast?
Agitation, aggression, anxiety, abnormal dreams, depression, and suicidal thoughts or behaviour carry a boxed warning with this drug. Document a baseline mood before starting therapy and report any new changes promptly, especially in adolescents.
Is montelukast safe to use instead of an inhaled corticosteroid?
It is usually an add-on, not a replacement. Stopping inhaled corticosteroid therapy in favour of montelukast without prescriber direction can leave asthma undertreated.
How long does montelukast take to work?
It builds a preventive effect over days rather than acting immediately, so improvement in symptom frequency and rescue inhaler use is usually assessed over one to two weeks of consistent daily dosing.