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 (seasonal and perennial). It represents a distinct class of controller medication that works by blocking the action of specific inflammatory molecules called leukotrienes, which are central to the pathophysiology of bronchoconstriction and allergic inflammation. This oral tablet, chewable tablet, or granule formulation offers a non-steroidal, targeted approach to managing underlying inflammatory processes, providing a valuable option within a comprehensive asthma and allergy management plan.

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), chewable tablets (4 mg and 5 mg), and oral granules (4 mg packet).
• Mechanism of Action: Binds with high affinity and selectivity to the CysLT1 receptor, blocking the action of leukotrienes LTC4, LTD4, and LTE4.
• Administration: Once-daily oral dosing, without regard to meals (except for oral granules, which must be administered within 15 minutes of opening the packet).
• Prescription Status: Available by prescription only.

Benefits

• Provides prophylactic control of persistent asthma, reducing the frequency of daytime and nighttime symptoms.
• Improves lung function parameters, as measured by forced expiratory volume in 1 second (FEV1), and reduces the need for rescue short-acting beta-agonist (SABA) inhaler use.
• Offers effective relief from the symptoms of allergic rhinitis, including sneezing, nasal congestion, rhinorrhea, and pruritus.
• Serves as an alternative first-line controller medication for mild persistent asthma, particularly in patients who prefer an oral formulation or cannot adequately use inhaled corticosteroids (ICS).
• Can be used as add-on therapy to inhaled corticosteroids in patients not adequately controlled on ICS alone, providing a synergistic anti-inflammatory effect through a different pathway.
• Helps prevent exercise-induced bronchoconstriction (EIB) when taken at least 2 hours before exercise.

Common use

Singulair is commonly prescribed for the chronic management of asthma in patients aged 12 months and older. It is not indicated for the reversal of acute asthma attacks. Its primary role is as a controller medication to reduce underlying inflammation and bronchial hyperresponsiveness. It is also widely used for the treatment of seasonal allergic rhinitis (outdoor allergies) in patients aged 2 years and older, and perennial allergic rhinitis (indoor allergies) in patients aged 6 months and older. Furthermore, it is indicated for the prevention of exercise-induced bronchoconstriction in patients aged 15 years and older.

Dosage and direction

Dosage is based on the indication and the age of the patient. It is administered once daily in the evening for asthma and allergic rhinitis. For exercise-induced bronchoconstriction, it should be taken at least 2 hours before exercise and not more than once in a 24-hour period.

• Asthma & 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 packet of 4 mg oral granules daily.
  • Pediatric Patients (12 to 23 months of age): One packet of 4 mg oral granules daily.
  • Pediatric Patients (6 to 11 months of age): One packet of 4 mg oral granules 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, 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 opening the packet. The granules are not intended to be dissolved in liquid, but the dose may be swallowed with water or breast milk after administration.

Precautions

Patients should be advised that Singulair is not a bronchodilator and should not be used to treat acute asthmatic attacks. Acute exacerbations require an inhaled short-acting beta-agonist. Patients should have such rescue medication available at all times. Physicians should monitor patients for neuropsychiatric events (see Side Effects). Do not abruptly substitute Singulair for inhaled or oral corticosteroids; the dose of corticosteroids should be reduced gradually under medical supervision. Patients with known aspirin sensitivity should continue avoidance of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) while taking Singulair, as it may not fully protect against bronchospasm in these patients. Exposure to montelukast in utero has been associated with an increased risk for major congenital malformations; the benefit of treatment during pregnancy must be weighed against potential risks.

Contraindications

Singulair is contraindicated in patients with a known hypersensitivity to montelukast or any of the excipients in the formulation. Hypersensitivity reactions, including anaphylaxis, can occur.

Possible side effect

The most common adverse reactions in clinical trials (≥1% and greater than placebo) for adults and adolescents included headache, influenza, abdominal pain, cough, and dyspepsia. In pediatric patients, adverse reactions also included fever, otitis media, pharyngitis, sinusitis, and rhinorrhea.

Serious side effects have been reported and include:

• Neuropsychiatric events: Postmarketing reports include agitation, aggressive behavior or hostility, anxiety, depression, disorientation, disturbance in attention, dream abnormalities, hallucinations, insomnia, irritability, memory impairment, obsessive-compulsive symptoms, restlessness, somnambulism (sleepwalking), suicidal ideation and behavior (including suicide), tics, tremor. These events have been reported in patients with and without a pre-existing history of psychiatric disorder. Patients and caregivers should be advised to monitor for changes in behavior or mood.
• Eosinophilic conditions: In rare cases, patients on montelukast have presented with systemic eosinophilia, sometimes presenting with clinical features of vasculitis consistent with Churg-Strauss syndrome. This has often been associated with the reduction of oral corticosteroid therapy.
• Allergic reactions: Including hypersensitivity reactions (e.g., anaphylaxis, hepatic eosinophilic infiltration), rash, and hives.

Drug interaction

Formal drug interaction studies have shown no clinically significant impact on the pharmacokinetics of digoxin, warfarin, theophylline, oral contraceptives (ethinyl estradiol/norethindrone), terfenadine, or prednisone. Montelukast is metabolized by CYP450 enzymes (primarily CYP2C8 and CYP3A4). Concomitant administration with potent CYP2C8 inhibitors (e.g., gemfibrozil) may increase montelukast plasma concentrations. Phenobarbital, a potent CYP2C8 and CYP3A4 inducer, decreases the AUC of montelukast. Clinicians should be aware of the potential for such interactions.

Missed dose

If a dose is missed, it should be skipped and the next dose taken at the regular time the following day. The patient should not take a double dose to make up for the missed one.

Overdose

Experience in marketed use is limited. In chronic asthma studies, doses up to 200 mg per day were administered and were generally tolerated without serious adverse events. The most frequently reported symptoms of overdose included thirst, somnolence, mydriasis (pupil dilation), hyperkinesia, and abdominal pain. There is no specific antidote for montelukast overdose. Treatment should be supportive and symptomatic. It is not known if montelukast is removed by peritoneal 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). Keep in the original container and protect from moisture and light. Keep the bottle tightly closed. Do not remove the desiccant (drying agent) from the bottle. Keep all medications 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 medication. Never disregard professional medical advice or delay in seeking it because of something you have read here. The prescribing information provided by the manufacturer is the ultimate authority on the safe and effective use of this product.

Reviews

• “As a pulmonologist, I find Singulair to be a valuable tool in my arsenal, particularly for younger patients struggling with inhaler technique or as add-on therapy for those with a significant allergic component to their asthma. The once-daily dosing aids in adherence.” – Dr. A. Sharma, MD
• “This medication has been a game-changer for my son’s perennial allergic rhinitis and mild asthma. It significantly reduced his nighttime coughing and nasal symptoms. We did not observe any behavioral side effects, but I remain vigilant as advised.” – Parent of a 7-year-old patient.
• “In my allergy practice, I use montelukast frequently for patients with allergic rhinitis who also have a component of asthma. The dual benefit is often appreciated. I always have a detailed discussion about the potential for neuropsychiatric side effects before initiating therapy.” – Dr. L. Chen, Allergy & Immunology
• “I’ve been using Singulair for exercise-induced bronchoconstriction for two years. Taking it before my soccer games means I can play a full match without needing my rescue inhaler. It’s been incredibly reliable for this specific purpose.” – 28-year-old athlete.