What Is Singulair and How Does It Work?
Singulair, with its generic equivalent montelukast, is a type of drug known as a leukotriene receptor antagonist. To understand how it works, one must first grasp the role of leukotrienes. These are inflammatory chemicals that the body releases in response to an allergic trigger or other irritants. In conditions like asthma and allergic rhinitis, leukotrienes can cause the tightening of muscles around the airways (bronchoconstriction), excess mucus production, and general inflammation. By blocking the action of these leukotrienes, Singulair helps prevent these symptoms from occurring, rather than treating an existing attack.
Unlike an antihistamine, which blocks the effects of histamine, Singulair works on a different inflammatory pathway. This makes it a distinct therapeutic option, particularly useful for individuals with a history of both asthma and allergic conditions. It is available in several forms, including oral tablets, chewable tablets, and granules, to accommodate different age groups.
The Primary Uses for Singulair
Asthma Management
Singulair is a key component in the long-term control and prevention of asthma symptoms in adults and children as young as 12 months. It is not a rescue inhaler for an acute asthma attack and works best when taken consistently, as prescribed. For asthma, it is typically taken once daily in the evening.
Common asthma symptoms managed by Singulair include:
- Wheezing
- Coughing
- Chest tightness
- Difficulty breathing
Prevention of Exercise-Induced Bronchoconstriction (EIB)
For adults and children aged 6 years and older, Singulair can be used to prevent breathing difficulties that occur during physical exercise. For this purpose, it is usually taken at least two hours before exercise. Patients who already take Singulair daily for asthma should not take an extra dose for EIB.
Allergic Rhinitis Treatment
Singulair is approved to treat the symptoms of allergic rhinitis, commonly known as hay fever. This includes both seasonal allergies triggered by things like pollen, and perennial (year-round) allergies caused by indoor allergens like dust mites and pet dander. However, the FDA recommends using it for allergic rhinitis only in patients who have an inadequate response or intolerance to alternative therapies due to the risk of neuropsychiatric side effects.
Common allergy symptoms addressed by Singulair include:
- Sneezing
- Nasal congestion
- Runny nose
- Itchy nose, throat, and eyes
Comparison with Other Allergy and Asthma Medications
| Feature | Singulair (Montelukast) | Antihistamines (e.g., Zyrtec) | Nasal Corticosteroids (e.g., Flonase) |
|---|---|---|---|
| Mechanism | Blocks leukotrienes, reducing inflammation and muscle constriction. | Blocks histamine receptors, preventing an allergic response. | Reduces inflammation in nasal passages by blocking multiple inflammatory substances. |
| Primary Use | Long-term control of asthma, EIB, and allergic rhinitis. | Relief of allergy symptoms like sneezing, itching, and runny nose. | Relief of nasal congestion and inflammation for allergic rhinitis. |
| Effectiveness | Moderate, often used as an add-on treatment or second-line for allergies. | Highly effective for standard allergy symptoms. | Highly effective for nasal symptoms, especially congestion. |
| Availability | Prescription only. | Over-the-counter (OTC). | Both OTC and prescription. |
| Onset | May take several weeks for full effect. | Works relatively quickly. | Can take several days for full effect. |
| FDA Warning | Has a boxed warning for neuropsychiatric events. | No boxed warning for neuropsychiatric events. | No boxed warning for neuropsychiatric events. |
Potential Side Effects and FDA Boxed Warning
While Singulair is generally well-tolerated, it is associated with a range of side effects, some of which are serious and led to a black box warning from the FDA. It is important to discuss these risks with a healthcare provider.
Common side effects
- Headache
- Stomach pain or diarrhea
- Fever or flu-like symptoms
- Upper respiratory infection
- Cough
Serious neuropsychiatric side effects
In 2020, the FDA issued a boxed warning for Singulair (and its generic montelukast) regarding the risk of serious mood- and behavior-related changes. These effects can occur in patients with or without a prior history of mental illness. Patients and caregivers should be vigilant for any changes in behavior.
Serious side effects to watch for include:
- Agitation or aggressive behavior
- Anxiety and depression
- Sleep disturbances, including nightmares or insomnia
- Memory problems or difficulty concentrating
- Hallucinations
- Suicidal thoughts and behaviors
If any of these serious side effects occur, patients should stop taking Singulair and contact a healthcare professional immediately. The FDA has specified that due to these risks, Singulair should only be used for allergic rhinitis when other treatments have failed.
Conclusion
Singulair (montelukast) is a prescription medication primarily used for the long-term control of asthma, prevention of exercise-induced breathing problems, and treatment of allergic rhinitis. It works by blocking inflammatory leukotrienes, which distinguishes it from other common allergy medications like antihistamines and nasal steroids. However, it comes with a serious FDA boxed warning regarding potential neuropsychiatric side effects, including suicidal thoughts and behaviors. Given these risks, a thorough discussion with a healthcare provider is essential before starting or continuing treatment, particularly for patients with mild allergy symptoms where other, safer alternatives exist. For those with asthma, it is a key controller but never a substitute for a rescue inhaler during an acute attack.
