Singulair (montelukast sodium) is a leukotriene receptor antagonist (LTRA) prescription medication indicated for the prophylaxis and chronic treatment of asthma in adults and pediatric patients, as well as for the relief of symptoms of allergic rhinitis. It represents a distinct therapeutic class, offering a non-steroidal, oral option for managing underlying inflammatory pathways. This agent works by selectively blocking the action of cysteinyl leukotrienes, which are potent inflammatory mediator molecules released in the body in response to allergens and other triggers. By inhibiting these mediators, Singulair helps prevent the bronchoconstriction, airway edema, and inflammatory cell migration associated with asthmatic and allergic responses, providing a targeted approach to disease management.

Features

• Active Pharmaceutical Ingredient: Montelukast sodium.
• Drug Class: Selective and orally active leukotriene receptor antagonist that inhibits the cysteinyl leukotriene (CysLT1) receptor.
• Available Formulations: Film-coated tablets (10 mg, 4 mg, 5 mg), chewable tablets (4 mg, 5 mg), and oral granules (4 mg packet).
• Administration Route: Oral, once daily in the evening.
• Mechanism of Action: Binds with high affinity and selectivity to the CysLT1 receptor, blocking the action of leukotrienes LTC4, LTD4, and LTE4.

Benefits

• Provides 24-hour control of underlying inflammation, reducing the frequency and severity of asthma exacerbations.
• Improves overall asthma control, as measured by a reduction in daytime and nighttime symptoms and a decreased need for rescue short-acting beta-agonist inhalers.
• Offers a convenient, once-daily oral dosing regimen, which may improve adherence compared to inhaled therapies, particularly in pediatric populations.
• Effectively relieves symptoms of seasonal and perennial allergic rhinitis, including sneezing, rhinorrhea, nasal congestion, and pruritus.
• Serves as a prophylactic treatment for exercise-induced bronchoconstriction (EIB), taken at least 2 hours before physical activity.
• Provides a non-steroidal alternative or adjunctive therapy for patients whose asthma is not adequately controlled on inhaled corticosteroids.

Common use

Singulair is commonly prescribed for the chronic management of mild to moderate persistent asthma in patients aged 12 months and older. It is not indicated for the reversal of acute asthma attacks. It is also approved for the treatment of symptoms of allergic rhinitis (seasonal and perennial) in patients aged 2 years and older. Furthermore, it is used for the prevention of exercise-induced bronchoconstriction (EIC) in patients 15 years of age and older. It is often used as add-on therapy when low-to-medium dose inhaled corticosteroids provide insufficient control or as monotherapy for patients who cannot or will not use inhaled corticosteroids.

Dosage and direction

The dosage of Singulair is based on the indication and the age of the patient. It is administered orally once daily in the evening for asthma and allergic rhinitis. For exercise-induced bronchoconstriction, one tablet should be taken at least 2 hours before exercise; a second dose should not be taken within 24 hours.

• Asthma and Allergic Rhinitis:

  • Adults and Adolescents (15 years of age and older): One 10 mg tablet daily.
  • Pediatric Patients (6 to 14 years of age): One 5 mg chewable tablet daily.
  • Pediatric Patients (2 to 5 years of age): One 4 mg chewable tablet or one 4 mg oral granule packet daily.
  • Pediatric Patients (12 to 23 months of age): One 4 mg oral granule packet daily.

• Exercise-Induced Bronchoconstriction:

  • Adults and Adolescents (15 years of age and older): One 10 mg tablet at least 2 hours before exercise.

The oral granules can be administered directly in the mouth, dissolved in 5 mL (1 teaspoon) 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 administered within 15 minutes of preparation. Do not store any mixed product for future use.

Precautions

Patients should be advised that Singulair is not for the treatment of acute asthma attacks and that they should have appropriate rescue medication available at all times. No abrupt substitution of Singulair for inhaled or oral corticosteroids is recommended; corticosteroid doses should be reduced gradually under medical supervision. Healthcare professionals should monitor patients for neuropsychiatric events (e.g., agitation, aggression, depression, sleep disturbances, suicidal thoughts and behavior). Patients and caregivers should be advised to be alert for such changes and to report them immediately. Caution is recommended in patients with pre-existing psychiatric conditions. Phenylketonuria patients should be informed that the 4 mg and 5 mg chewable tablets contain aspartame, a source of phenylalanine.

Contraindications

Singulair is contraindicated in patients with known hypersensitivity to any component of the product. Hypersensitivity reactions have been reported with montelukast, including anaphylaxis, angioedema, rash, and urticaria.

Possible side effect

The most common adverse reactions in clinical trials (incidence ≥5% and greater than placebo) were upper respiratory infection, fever, headache, pharyngitis, cough, abdominal pain, diarrhea, influenza, rhinorrhea, sinusitis, otitis media, and nausea. Serious side effects, though less common, require immediate medical attention. These include:

• Neuropsychiatric events: Agitation including aggressive behavior, bad/vivid dreams, depression, disorientation, hallucinations, insomnia, irritability, restlessness, suicidal thinking and behavior, tremor, anxiety, sleepwalking.
• Systemic eosinophilia: Cases of eosinophilic conditions, including Churg-Strauss syndrome (a systemic vasculitis), have been reported, often but not exclusively in association with the reduction of oral corticosteroid therapy.
• Hypersensitivity reactions: Including anaphylaxis, angioedema, rash, and urticaria.

Drug interaction

Formal drug interaction studies have shown Singulair (montelukast) is not clinically importantly inhibited by theophylline or prednisone. It does not inhibit CYP 2C8, 2C9, 2A6, 2B6, 2C19, 2D6, 2E1, or 3A4. Montelukast is metabolized by CYP 2C8, 2C9, and 3A4. Concomitant administration with potent inducers of CYP 2C8 (e.g., rifampin) may decrease the systemic exposure of montelukast. Gemfibrozil, a strong inhibitor of CYP 2C8, significantly increases plasma concentrations of montelukast. Phenobarbital, which induces CYP 2C9, decreases the AUC of montelukast.

Missed dose

If a dose is missed, it should be skipped. The patient should take the next prescribed dose at the regular time. Do not double the dose to make up for the missed one. Maintaining the once-daily schedule is important for consistent therapeutic effect.

Overdose

Experience in marketed use includes reported overdosage. The most frequently reported symptoms included thirst, somnolence, vomiting, psychomotor hyperactivity, and headache. In the event of an overdose, the patient should be treated supportively, and the symptoms should be managed. It is advisable to contact a poison control center or healthcare provider for current guidance on the management of overdose.

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 and keep it tightly closed to protect from moisture and light. The 4 mg and 5 mg chewable tablets contain aspartame and must be protected from heat and high humidity. Keep this and all medications out of the reach of children.

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 or changing any treatment regimen. Never disregard professional medical advice or delay in seeking it because of something you have read here. The content has been compiled from various sources believed to be accurate and reliable, but no warranty, expressed or implied, is made regarding its accuracy, completeness, or timeliness.

Reviews

• “As a pulmonologist, I find Singulair to be a valuable add-on therapy for my moderate asthmatic patients who still experience breakthrough symptoms on medium-dose ICS. Its once-daily dosing promotes excellent adherence.” – Dr. A. Reynolds, MD.
• “Prescribing the granule formulation for my pediatric patients under 5 has been a game-changer. It provides us with a non-inhaled option to control their persistent cough and wheeze, and parents find the administration straightforward.” – Dr. L. Chen, Pediatrician.
• “I’ve been using Singulair for my exercise-induced asthma for years. Taking it a few hours before a run completely prevents the tightness and wheezing I used to experience. It’s an essential part of my routine.” – M. Davies, Patient.
• “While effective for many, I always counsel my patients and their families on the potential for mood-related side effects. We establish a clear plan to report any behavioral changes immediately.” – Dr. P. Sharma, Allergist/Immunologist.
• “It didn’t work for my year-round allergies as well as a nasal steroid, but it did help reduce my reliance on antihistamines. It’s a good option for multi-symptom control.” – J. Tolbert, Patient.