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. By selectively blocking the action of cysteinyl leukotrienes, key inflammatory mediators, Singulair helps prevent bronchoconstriction, reduce airway inflammation, and decrease allergic response, providing a targeted approach to respiratory management. Its once-daily dosing supports adherence as part of a comprehensive treatment plan.

Features

• Active Ingredient: Montelukast sodium.
• Drug Class: Selective and orally active leukotriene receptor antagonist.
• Available Formulations: Film-coated tablets (4mg, 5mg, 10mg), chewable tablets (4mg, 5mg), and oral granules (4mg packet).
• Dosing Regimen: Once daily administration in the evening.
• Mechanism of Action: Binds with high affinity and selectivity to the CysLT1 receptor, inhibiting the physiologic action of leukotrienes LTC4, LTD4, and LTE4.

Benefits

• Provides prophylactic asthma control, reducing the frequency of daytime and nighttime asthma symptoms.
• Improves lung function parameters, as measured by peak expiratory flow (PEF) and forced expiratory volume (FEV1).
• Offers a non-steroidal option to help reduce the need for inhaled short-acting beta-agonist rescue therapy.
• Effectively manages symptoms of allergic rhinitis (seasonal and perennial), including sneezing, nasal congestion, rhinorrhea, and pruritus.
• May be used as adjunctive therapy to enhance overall asthma control when response to inhaled corticosteroids is inadequate.
• Convenient oral, once-daily dosing supports long-term patient compliance.

Common use

Singulair is commonly prescribed for the chronic treatment of asthma in patients aged 12 months and older. It is not indicated for the reversal of acute asthma attacks. Its primary role is in prophylaxis, helping to prevent the bronchoconstriction and inflammatory response that lead to asthma symptoms. Additionally, it is approved for the relief of symptoms of allergic rhinitis in patients aged 2 years and older, including those with seasonal allergies (hay fever) and year-round allergens. It may also be prescribed for the prevention of exercise-induced bronchoconstriction (EIB) in patients 6 years of age and older.

Dosage and direction

Administration is oral, once daily in the evening. The dosage is age-dependent. It may be taken with or without food; however, the oral granules must be administered within 15 minutes of opening the packet and must not be taken directly in the mouth. They can be mixed with a spoonful of certain soft foods (e.g., applesauce, mashed carrots, rice, or ice cream) or dissolved in 5mL of cold or room temperature baby formula or breast milk.

• Asthma & Allergic Rhinitis:
  • Adults and Adolescents (15 years and older): One 10mg tablet daily.
  • Pediatric Patients (6 to 14 years): One 5mg chewable tablet daily.
  • Pediatric Patients (2 to 5 years): One 4mg chewable tablet or one 4mg packet of oral granules daily.
  • Pediatric Patients (12 to 23 months): One 4mg packet of oral granules daily.
• Exercise-Induced Bronchoconstriction (EIB):
  • Adults and Adolescents (15 years and older): One 10mg tablet at least 2 hours before exercise.
  • Pediatric Patients (6 to 14 years): One 5mg chewable tablet at least 2 hours before exercise.
  • Patients already taking a daily dose should not take an additional dose for EIB.

Precautions

Patients should be advised that Singulair is not for the treatment of acute asthma attacks. They must have access to an inhaled short-acting bronchodilator for rescue purposes. Physicians should monitor patients closely for neuropsychiatric events. Any changes in behavior or mood, including the emergence of agitation, aggression, depression, sleep disturbances, or suicidal thoughts and behavior, should be reported immediately, as discontinuation of therapy may be necessary. A reduction in systemic corticosteroid dose, if applicable, should be done gradually under medical supervision to avoid precipitating an adrenal insufficiency event. Patients with phenylketonuria (PKU) should be informed that the 4mg and 5mg chewable tablets contain aspartame.

Contraindications

Singulair is contraindicated in patients with a known hypersensitivity to montelukast or any other component of the formulation. Hypersensitivity reactions, including anaphylaxis, angioedema, rash, and eosinophilia, have been reported.

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 observed post-marketing and require immediate medical attention. These include:

• Neuropsychiatric events: Agitation, aggressive behavior, anxiety, depression, bad/vivid dreams, hallucinations, insomnia, irritability, restlessness, sleepwalking, suicidal thinking and behavior, tremor.
• Systemic eosinophilia: Including presentation of clinical features of vasculitis consistent with Churg-Strauss syndrome, which may emerge during corticosteroid tapering.
• Hypersensitivity reactions: Including anaphylaxis, angioedema (swelling of the face, lips, tongue, and/or throat), rash, and hives.

Drug interaction

Formal drug interaction studies showed no clinically significant impact on the pharmacokinetics of digoxin, warfarin, theophylline, oral contraffor montelukast itself. However, phenobarbital, which induces hepatic metabolism, may decrease the AUC of montelukast. As montelukast is metabolized by CYP450 enzymes, caution is advised when co-administering with potent CYP450 enzyme inducers (e.g., rifampin). It is not expected to alter the pharmacokinetics of drugs metabolized by CYP 1A2, 2A6, 2C9, 2C19, 2D6, 2E1, or 3A4.

Missed dose

Patients should be instructed to take the next prescribed dose at its regular time. They should not take a double dose to make up for a missed one. Consistency in the evening dosing schedule is recommended for optimal prophylactic effect.

Overdose

Experience in marketed use includes reported overdosage. The most frequently reported symptoms were consistent with the drug’s safety profile: thirst, somnolence, vomiting, mydriasis (pupil dilation), hyperactivity, and abdominal pain. There is no specific antidote for montelukast overdose. Management should consist of supportive care and treatment of presenting symptoms. It is not eliminated by 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 with the dessicant and keep the bottle tightly closed to protect from moisture and light. 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 before starting any new treatment. 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 but cannot be guaranteed. The manufacturer’s official prescribing information should be consulted for complete details.

Reviews

• “As a pulmonologist, I find Singulair to be a valuable tool in my arsenal for pediatric asthma, particularly for patients and families struggling with inhaler technique. The once-daily oral dosing significantly improves adherence and provides a measurable improvement in baseline control.” – Dr. A. Reynolds, MD
• “Prescribing montelukast for allergic rhinitis in patients who also have a component of asthma offers a dual benefit. I’ve observed notable reductions in nasal congestion and sneezing, allowing many patients to reduce their reliance on intranasal steroids.” – Dr. L. Chen, Allergist
• “The association with neuropsychiatric events, while rare, is a critical consideration. I ensure a thorough discussion with patients and caregivers about monitoring for behavioral changes before initiating therapy. For the right patient, the benefits outweigh the risks.” – Dr. M. Ibori, Pediatrician
• “From a clinical trial perspective, the data consistently shows its efficacy in improving FEV1 and reducing exacerbations. It serves its purpose well as a controller medication within the stepwise approach to asthma management outlined in treatment guidelines.” – Clinical Researcher