Montelukast is a leukotriene receptor antagonist (LTRA) that plays a key role in the long-term management of asthma, allergic rhinitis, and exercise-induced bronchoconstriction. Leukotrienes are inflammatory mediators derived from arachidonic acid through the 5-lipoxygenase pathway. They contribute to airway inflammation, edema, smooth muscle contraction, and increased mucus production. By selectively blocking leukotriene D4 at the cysteinyl leukotriene receptor (CysLT1) found in the airway and on other pro-inflammatory cells, montelukast reduces these inflammatory processes and helps maintain open airways.
Unlike inhaled corticosteroids, which act broadly on many aspects of inflammation, montelukast provides a targeted mechanism of action. It is administered orally, once daily, making it appealing for patients who prefer pills over inhalers. This route of administration also makes it especially suitable for children, as chewable tablets and granule formulations are widely available.
Since its approval in the late 1990s, montelukast has become a widely prescribed adjunctive therapy for asthma, especially in patients with mild persistent asthma, those with allergic triggers, or those who do not tolerate inhaled steroids well. It does not provide immediate relief of acute asthma symptoms but rather works preventively over time. Montelukast’s convenience and safety profile have contributed to its popularity, but its neuropsychiatric side effects have prompted regulatory agencies, including the EMA and FDA, to issue strong warnings about risks such as depression, agitation, and suicidal thoughts, which require careful patient counseling and monitoring.
Overall, montelukast is a valuable option for selected patients with asthma or allergic conditions, provided clinicians and patients are vigilant about side effect monitoring and use it as part of a broader management plan that includes environmental control, trigger avoidance, and, where necessary, additional pharmacotherapy.
Montelukast is indicated in several conditions where leukotrienes contribute to pathophysiology:
How it should not be used: Montelukast is not a rescue medication and should never be used to treat acute asthma attacks. It does not replace inhaled corticosteroids in moderate to severe asthma but can be combined with them as part of stepwise therapy. Its role in chronic obstructive pulmonary disease (COPD) is not well established and is generally not recommended outside experimental use.
Clinicians typically re-evaluate the benefit of montelukast after a trial period. If symptoms remain uncontrolled, escalation to inhaled corticosteroids or combination inhalers may be necessary. Adherence is crucial; missing doses can reduce effectiveness as montelukast relies on steady receptor blockade rather than rapid onset bronchodilation.
Overall, montelukast is considered safe for most patients, but the neuropsychiatric risks necessitate careful patient selection and monitoring. Clinicians must balance its benefits with these potential harms and encourage patients to stop treatment and seek help if concerning symptoms appear.
Patients should be counseled not to stop prescribed steroids suddenly when starting montelukast, and clinicians should always review comorbidities and concomitant medications.
Montelukast is metabolized by cytochrome P450 enzymes, particularly CYP3A4 and CYP2C9. However, clinically significant interactions are relatively rare. Known and potential interactions include:
Patients should always inform their healthcare provider about all medicines, vitamins, or herbal supplements to ensure safe use.
Overdose: Symptoms from large ingestions include abdominal pain, thirst, sleepiness, headache, vomiting, and psychomotor hyperactivity. Supportive care is the cornerstone of treatment. There is no specific antidote. Patients should be monitored for signs of neuropsychiatric reactions even in the context of overdose.
Accidental double dose: Usually not harmful, but patients should be observed for increased side effects such as headache or abdominal discomfort. Instruct patients not to take any further doses until the next scheduled dose.
Missed dose: Take as soon as remembered unless it is almost time for the next scheduled dose. Never double up to make up for a missed dose, as this increases the risk of side effects without added benefit. Consistency is important for preventive effect, particularly in asthma control.
Patients should always be advised to read the package leaflet carefully and consult their clinician or pharmacist if unsure about dosing.
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