Singulair

Singulair (montelukast sodium) is a prescription leukotriene receptor antagonist (LTRA) specifically formulated for the prophylactic and chronic treatment of asthma, and for the relief of symptoms of allergic rhinitis. It represents a distinct class of controller medication that targets the underlying inflammatory pathways mediated by cysteinyl leukotrienes, key mediators in the asthmatic and allergic response. By selectively blocking these receptors, Singulair prevents bronchoconstriction, reduces eosinophilic inflammation, and decreases vascular permeability, offering a non-steroidal option for long-term management. Its oral formulation provides a convenient, once-daily dosing regimen suitable for both adult and pediatric populations, as young as 12 months for asthma and 2 years for allergic rhinitis.

Features

• Active Pharmaceutical Ingredient: Montelukast sodium.
• Pharmacologic Class: Selective and orally active leukotriene receptor antagonist that inhibits the cysteinyl leukotriene (CysLT1) receptor.
• Available Formulations: Film-coated tablets (10 mg, 5 mg, 4 mg), chewable tablets (4 mg, 5 mg), and oral granules packets (4 mg).
• Dosing Regimen: Once daily administration, typically in the evening.
• Mechanism of Action: Competitively antagonizes the CysLT1 receptor, blocking the action of leukotrienes LTC4, LTD4, and LTE4.
• Prescription Status: Available by prescription only.

Benefits

• Provides 24-hour control of underlying airway inflammation, reducing the frequency and severity of asthma exacerbations.
• Effectively relieves perennial and seasonal allergic rhinitis symptoms, including sneezing, nasal congestion, rhinorrhea, and pruritus.
• Offers a non-steroidal treatment option, which is a significant consideration for patients averse to or requiring an adjunct to inhaled corticosteroids (ICS).
• Improves lung function parameters (FEV1) and reduces the need for rescue short-acting beta-agonists (SABAs) in asthmatic patients.
• Convenient oral dosing supports improved adherence compared to inhaled therapies, particularly in pediatric and adolescent populations.
• Can be used as adjunctive therapy to enhance overall asthma control when response to inhaled corticosteroids is inadequate.

Common use

Singulair is indicated for the prophylaxis and chronic treatment of asthma in adults and pediatric patients 12 months of age and older. It is also indicated for the relief of symptoms of allergic rhinitis (seasonal and perennial) in adults and pediatric patients 2 years of age and older. For asthma, it is used to prevent symptoms, including those induced by exercise (exercise-induced bronchoconstriction). It is not indicated for the reversal of acute asthma attacks. For allergic rhinitis, it is used to manage symptoms such as sneezing, nasal itching, rhinorrhea, and nasal congestion.

Dosage and direction

Administration is oral, once daily in the evening. The dosage is based on the indication and the patient’s age.

• Asthma & Allergic Rhinitis in patients 15 years of age and older: One 10 mg tablet daily.
• Asthma in patients 6 to 14 years of age: One 5 mg chewable tablet daily.
• Asthma in patients 2 to 5 years of age: One 4 mg chewable tablet or one 4 mg oral granule packet daily.
• Asthma in patients 12 to 23 months of age: One 4 mg oral granule packet daily.
• Allergic Rhinitis in patients 2 to 14 years of age: Dosing is the same as for asthma for the respective age groups. The granules must be administered within 15 minutes of opening the packet and can be placed directly in the mouth, dissolved in 5 mL of cold or room temperature baby formula or breast milk, or mixed with a spoonful of one of the following soft foods at cold or room temperature: applesauce, mashed carrots, rice, or ice cream. The entire dose must be consumed.

Precautions

Patients should be advised that Singulair is not for the treatment of acute asthma attacks and should have access to an inhaled short-acting bronchodilator for rescue. Physicians should monitor patients for neuropsychiatric events. Patients and caregivers should be alert for changes in behavior or mood, including agitation, aggression, depression, sleep disturbances, and suicidal ideation, and report these to a healthcare provider immediately. The drug should be used with caution in patients on corticosteroid reduction regimens, as it is not a substitute for inhaled or oral corticosteroids. Abrupt reduction of corticosteroid doses may unmask underlying conditions previously suppressed by systemic corticosteroid therapy.

Contraindications

Singulair is contraindicated in patients with known hypersensitivity to montelukast or any other component of the formulation. Hypersensitivity reactions may include anaphylaxis, angioedema, rash, and eosinophilia.

Possible side effect

The most common adverse reactions in clinical trials were generally mild and included headache, influenza, abdominal pain, cough, and dyspepsia. However, serious side effects have been reported and require immediate medical attention. These include:

• Neuropsychiatric events: Agitation, aggressive behavior or hostility, anxiety, depression, bad/vivid dreams, hallucinations, insomnia, irritability, restlessness, sleepwalking, suicidal thoughts and behavior (including suicide), tremor.
• Systemic eosinophilia: Sometimes presenting with clinical features of vasculitis consistent with Churg-Strauss syndrome, which may occur in patients tapering off oral corticosteroid therapy.
• Hypersensitivity reactions: Including anaphylaxis, angioedema, rash, and urticaria.
• Other: Increased bleeding tendency, hepatic eosinophilic infiltration, hepatitis.

Drug interaction

Formal drug interaction studies showed no clinically significant inhibition of cytochrome P450 enzymes. However, phenobarbital, which induces hepatic metabolism, decreased the AUC of montelukast approximately 40%. No dosage adjustment is recommended, but clinicians should be aware of the potential for reduced efficacy. Montelukast may be safely co-administered with commonly prescribed asthma medications, including theophylline, prednisone, prednisolone, inhaled fluticasone, and digoxin. It does not potentiate the effects of alcohol.

Missed dose

Patients should be instructed to take the next prescribed dose at the regular time. They should not take a double dose to make up for the missed one. Maintaining the once-daily schedule is important for consistent therapeutic effect.

Overdose

Experience in marketed use and clinical trials is limited. In chronic asthma studies, montelukast has been administered at doses up to 200 mg per day to patients for approximately one week without clinically important adverse experiences. In the event of an overdose, the patient should be treated supportively, and the symptoms should be managed. It is not known if montelukast is removed by peritoneal dialysis or hemodialysis.

Storage

Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C and 30°C (59°F and 86°F). Store in the original container or package to protect from moisture and light. Keep the bottle tightly closed. Do not remove the desiccant (drying agent) from the bottle. Keep all medicines out of the reach of children and pets.

Disclaimer

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any new treatment. Never disregard professional medical advice or delay in seeking it because of something you have read here. The side effects and other data listed are not exhaustive; other reactions may occur.

Reviews

• “As a pulmonologist, I find Singulair to be a valuable tool in my arsenal for moderate persistent asthma, particularly in younger patients who struggle with inhaler technique. Its anti-inflammatory action is distinct from ICS, and the combination often yields superior control.” – Dr. A. Sharma, MD.
• “Prescribing montelukast for my pediatric patients with concomitant asthma and significant allergic rhinitis has dramatically improved their quality of life and reduced school absences. The once-daily granules are a game-changer for toddlers.” – Dr. L. Chen, Pediatric Allergist.
• “The black box warning for neuropsychiatric events is critical. While many patients tolerate it well, I maintain a very low threshold for discontinuing therapy if any behavioral changes, even subtle ones like new nightmares, are reported by the parent or patient.” – Dr. R. Evans, Child Psychiatrist.
• “For managing exercise-induced bronchoconstriction in my adolescent athletes, Singulair provides reliable prevention without the need for pre-treatment with an inhaler, which they often forget. It’s been highly effective in this specific population.” – Dr. M. Ito, Sports Medicine.