Montelukast, a prescription medication also known by its brand name Singulair, is classified as a leukotriene receptor antagonist (LTRA). Unlike rescue inhalers, montelukast is a long-term controller medication used to manage and prevent symptoms of certain inflammatory respiratory diseases. It works by blocking specific inflammatory chemicals in the body called leukotrienes.
How Montelukast Works
Leukotrienes are released during allergic reactions and in chronic inflammatory conditions like asthma. They cause several effects, including airway narrowing, swelling, increased mucus production, and the recruitment of inflammatory cells. Montelukast works by blocking the action of leukotrienes at the CysLT$_{1}$ receptors, which helps reduce inflammation and improve breathing. This makes it effective in preventing symptoms associated with several conditions.
Primary Conditions Treated by Montelukast
The FDA has approved montelukast for the treatment and management of several diseases in various age groups.
Chronic Asthma
Montelukast is used for the long-term treatment and prevention of asthma symptoms in adults and children 12 months and older. It helps control symptoms like wheezing, coughing, and difficulty breathing but is not for treating sudden asthma attacks, which require a rescue inhaler.
Exercise-Induced Bronchoconstriction (EIB)
For individuals aged 6 and older, montelukast can prevent exercise-induced bronchoconstriction (EIB), taken at least two hours before exercise.
Allergic Rhinitis (Seasonal and Perennial)
Montelukast is used for relieving symptoms of both seasonal and perennial allergic rhinitis, such as sneezing, runny nose, and nasal itching. However, an FDA boxed warning advises reserving it for allergic rhinitis patients who have not responded well to or cannot tolerate other treatments due to the risk of serious mental health side effects.
Important Considerations and Side Effects
Montelukast can cause side effects, including serious ones highlighted by an FDA boxed warning.
Neuropsychiatric Events
A significant concern is the risk of serious neuropsychiatric events, which can occur during or after treatment in patients with or without a history of mental illness. Symptoms to watch for include agitation, anxiety, depression (including suicidal thoughts), sleep problems, memory issues, restlessness, and hallucinations. The FDA requires a boxed warning on the packaging to emphasize these risks. For allergic rhinitis, safer alternatives often make montelukast a second-line option.
Other Common Side Effects
More common side effects, typically less severe, can include headaches, stomach discomfort, cough, flu-like symptoms, sore throat, and diarrhea.
Table: Montelukast vs. Other Respiratory Medications
| Feature | Montelukast | Inhaled Corticosteroids (ICS) | Antihistamines |
|---|---|---|---|
| Mechanism | Leukotriene receptor antagonist; blocks inflammatory chemicals. | Potent anti-inflammatory; targets broader inflammatory pathways. | Histamine receptor blocker; targets allergic responses. |
| Primary Use | Controller medication for asthma, EIB, and allergies. | First-line controller for persistent asthma. | First-line treatment for allergic rhinitis. |
| Efficacy (Asthma) | Effective preventative option, especially when combined with other drugs. | Generally more effective than montelukast for reducing exacerbations. | No role in asthma treatment. |
| Efficacy (Allergies) | Effective for rhinitis symptoms, but second-line due to risks. | More effective than montelukast for allergic rhinitis. | Very effective for allergic rhinitis, especially for nasal symptoms. |
| Onset of Action | Starts working within a day for asthma symptoms. | Varies by medication, generally requires consistent use. | Fast-acting options available (e.g., Benadryl). |
| Major Safety Risk | FDA Boxed Warning for neuropsychiatric events. | Potential for local side effects (e.g., oral thrush) and systemic effects at high doses. | Sedation with older generations; generally safe with newer non-drowsy options. |
Conclusion
Montelukast is used to manage chronic asthma, prevent exercise-induced bronchoconstriction, and treat allergic rhinitis symptoms by blocking leukotrienes. However, it carries significant safety concerns, including a boxed warning from the FDA regarding serious neuropsychiatric side effects like agitation, depression, and suicidal thoughts. For allergic rhinitis, it is often not the preferred initial treatment. Patients should discuss risks and benefits with a healthcare provider and consider alternatives. More information on safety risks can be found in the {Link: FDA Drug Safety Communication https://www.fda.gov/drugs/drug-safety-and-availability/fda-requires-boxed-warning-about-serious-mental-health-side-effects-asthma-and-allergy-drug}.
