Montelukast sodium, the active ingredient in SINGULAIR, is a selective and orally active leukotriene receptor antagonist that inhibits the cysteinyl leukotriene CysLT 1 receptor. Montelukast sodium is described chemically as [ R -( E )]-1-[[[1-[3-[2-(7-chloro-2-quinolinyl)ethenyl]phenyl]-3-[2-(1-hydroxy-1-methylethyl)phenyl]propyl]thio]methyl]cyclopropaneacetic acid, monosodium salt. The empirical formula is C 35 H 35 ClNNaO 3 S, and its molecular weight is 608.18. The structural formula is: Montelukast sodium is a hygroscopic, optically active, white to off-white powder. Montelukast sodium is freely soluble in ethanol, methanol, and water and practically insoluble in acetonitrile. Each 10-mg film-coated SINGULAIR tablet contains 10.4 mg montelukast sodium, which is equivalent to 10 mg of montelukast, and the following inactive ingredients: microcrystalline cellulose, lactose monohydrate, croscarmellose sodium, hydroxypropyl cellulose, and magnesium stearate. The film coating consists of: hydroxypropyl methylcellulose, hydroxypropyl cellulose, titanium dioxide, red ferric oxide, yellow ferric oxide, and carnauba wax. Each 4-mg and 5-mg chewable SINGULAIR tablet contains 4.2 and 5.2 mg montelukast sodium, respectively, which are equivalent to 4 and 5 mg of montelukast, respectively. Both chewable tablets contain the following inactive ingredients: mannitol, microcrystalline cellulose, hydroxypropyl cellulose, red ferric oxide, croscarmellose sodium, cherry flavor, aspartame, and magnesium stearate. Each packet of SINGULAIR 4-mg oral granules contains 4.2 mg montelukast sodium, which is equivalent to 4 mg of montelukast. The oral granule formulation contains the following inactive ingredients: mannitol, hydroxypropyl cellulose, and magnesium stearate. image of montelukast sodium chemical structure

SINGULAIR is a leukotriene receptor antagonist indicated for: Prophylaxis and chronic treatment of asthma in patients 12 months of age and older. Acute prevention of exercise-induced bronchoconstriction (EIB) in patients 6 years of age and older. Relief of symptoms of allergic rhinitis (AR): seasonal allergic rhinitis (SAR) in patients 2 years of age and older, and perennial allergic rhinitis (PAR) in patients 6 months of age and older. Reserve use for patients who have an inadequate response or intolerance to alternative therapies. Limitations of Use: Not indicated to treat an acute asthma attack

Asthma SINGULAIR ® is indicated for the prophylaxis and chronic treatment of asthma in adults and pediatric patients 12 months of age and older

Exercise-Induced Bronchoconstriction (EIB) SINGULAIR is indicated for prevention of exercise-induced bronchoconstriction (EIB) in patients 6 years of age and older

Allergic Rhinitis SINGULAIR is indicated for the relief of symptoms of seasonal allergic rhinitis in patients 2 years of age and older and perennial allergic rhinitis in patients 6 months of age and older. Because the benefits of SINGULAIR may not outweigh the risk of neuropsychiatric symptoms in patients with allergic rhinitis , reserve use for patients who have an inadequate response or intolerance to alternative therapies

Limitations of Use SINGULAIR is not indicated for the treatment of an acute asthma attack.

Tablets: 10 mg, beige, rounded square-shaped, film-coated tablets, with code MSD 117 on one side and SINGULAIR on the other. Chewable Tablets: 5 mg, pink, round, bi-convex-shaped, with code MSD 275 on one side and SINGULAIR on the other. Chewable Tablets: 4 mg, pink, oval, bi-convex-shaped, with code MSD 711 on one side and SINGULAIR on the other. Oral Granules: 4 mg, white granules with 500 mg net weight, packed in a child-resistant foil packet. Tablets: 10 mg Chewable tablets: 5 mg and 4 mg Oral granules: 4 mg

Administration (by indications): Asthma: Once daily in the evening for patients 12 months and older. Acute prevention of EIB: One tablet at least 2 hours before exercise for patients 6 years of age and older. Seasonal allergic rhinitis: Once daily for patients 2 years and older. Perennial allergic rhinitis: Once daily for patients 6 months and older. Dosage (by age): 15 years and older: one 10-mg tablet. 6 to 14 years: one 5-mg chewable tablet. 2 to 5 years: one 4-mg chewable tablet or one packet of 4-mg oral granules. 6 to 23 months: one packet of 4-mg oral granules. Patients with both asthma and allergic rhinitis should take only one dose daily in the evening. For oral granules: Must administer within 15 minutes after opening the packet (with or without mixing with food)

Asthma For asthma, administer SINGULAIR orally once daily in the evening, with or without food. There have been no clinical trials in patients with asthma to evaluate the relative efficacy of morning versus evening dosing. The following doses are recommended: Table 1: Recommended Dosage in Asthma Age Dose Adult and adolescent patients 15 years of age and older one 10 mg tablet Pediatric patients 6 to 14 years of age one 5 mg chewable tablet Pediatric patients 2 to 5 years of age one 4 mg chewable tablet or one packet of oral granules Pediatric patients 12 to 23 months of age Safety and effectiveness in pediatric patients less than 12 months of age with asthma have not been established. one packet 4 mg oral granules Patients who miss a dose should take the next dose at their regular time and should not take 2 doses at the same time

Exercise-Induced Bronchoconstriction (EIB) For prevention of EIB, administer a single dose of SINGULAIR orally at least 2 hours, before exercise. The following doses are recommended: Table 2: Recommended Dosage in Exercise-Induced Bronchoconstriction (EIB) Age Dose Adult and adolescent patients 15 years of age and older one 10 mg tablet Pediatric patients 6 to 14 years of age Safety and effectiveness in patients younger than 6 years of age have not been established. one 5 mg chewable tablet An additional dose of SINGULAIR should not be taken within 24 hours of a previous dose. Patients already taking SINGULAIR daily for another indication (including chronic asthma) should not take an additional dose to prevent EIB. All patients should have available for rescue a short-acting β-agonist. Daily administration of SINGULAIR for the chronic treatment of asthma has not been established to prevent acute episodes of EIB

Allergic Rhinitis For allergic rhinitis, administer SINGULAIR orally once daily without regard to time of food ingestion. Time of administration in patients with allergic rhinitis can be individualized to suit patient needs. The following doses for the treatment of symptoms of seasonal allergic rhinitis are recommended: Table 3: Recommended Dosage in Seasonal Allergic Rhinitis Age Dose Adult and adolescent patients 15 years of age and older one 10 mg tablet Pediatric patients 6 to 14 years of age one 5 mg chewable tablet Pediatric patients 2 to 5 years of age Safety and effectiveness in pediatric patients younger than 2 years of age with seasonal allergic rhinitis have not been established. one 4 mg chewable tablet or one packet of 4 mg oral granules The following doses for the treatment of symptoms of perennial allergic rhinitis are recommended: Table 4: Recommended Dosage in Perennial Allergic Rhinitis Age Dose Adult and adolescent patients 15 years of age and older one 10 mg tablet Pediatric patients 6 to 14 years of age one 5 mg chewable tablet Pediatric patients 2 to 5 years of age one 4 mg chewable tablet or one packet of 4 mg oral granules Pediatric patients 6 to 23 months of age Safety and effectiveness in pediatric patients younger than 6 months of age with perennial allergic rhinitis have not been established. one packet of 4 mg oral granules Patients who miss a dose should take the next dose at their regular time and should not take 2 doses at the same time

Asthma and Allergic Rhinitis For patients with both asthma and allergic rhinitis, administer only one SINGULAIR dose orally once daily in the evening. Patients who miss a dose should take the next dose at their regular time and should not take 2 doses at the same time

Instructions for Administration of Oral Granules SINGULAIR 4-mg oral granules can be administered either directly in the mouth, dissolved in 1 teaspoonful (5 mL) of cold or room temperature baby formula or breast milk, or mixed with a spoonful of cold or room temperature soft foods; based on stability studies, only applesauce, carrots, rice, or ice cream should be used. The packet should not be opened until ready to use. After opening the packet, the full dose (with or without mixing with baby formula, breast milk, or food) must be administered within 15 minutes. If mixed with baby formula, breast milk, or food, SINGULAIR oral granules must not be stored for future use. Discard any unused portion. SINGULAIR oral granules are not intended to be dissolved in any liquid other than baby formula or breast milk for administration. However, liquids may be taken subsequent to administration. SINGULAIR oral granules can be administered without regard to the time of meals.

Do not prescribe SINGULAIR to treat an acute asthma attack. Advise patients to have appropriate rescue medication available. Inhaled corticosteroid may be reduced gradually. Do not abruptly substitute SINGULAIR for inhaled or oral corticosteroids. Patients with known aspirin sensitivity should continue to avoid aspirin or non-steroidal anti-inflammatory agents while taking SINGULAIR. Systemic eosinophilia, sometimes presenting with clinical features of vasculitis consistent with Churg-Strauss syndrome, has been reported. These events have been sometimes associated with the reduction of oral corticosteroid therapy ( 5.5 and 6.2 ). Inform patients with phenylketonuria that the 4-mg and 5-mg chewable tablets contain phenylalanine

Neuropsychiatric Events Serious neuropsychiatric (NP) events have been reported with use of SINGULAIR. These postmarketing reports have been highly variable and included, but were not limited to, agitation, aggressive behavior or hostility, anxiousness, depression, disorientation, disturbance in attention, dream abnormalities, dysphemia (stuttering), hallucinations, insomnia, irritability, memory impairment, obsessive-compulsive symptoms, restlessness, somnambulism, suicidal thoughts and behavior (including suicide), tic, and tremor. NP events have been reported in adult, adolescent, and pediatric patients with and without a previous history of psychiatric disorder. NP events have been reported mostly during SINGULAIR treatment, but some were reported after SINGULAIR discontinuation. Animal studies showed that montelukast distributes into the brain in rats ; however, the mechanisms underlying SINGULAIR-associated NP events are currently not well understood. Based upon the available data, it is difficult to identify risk factors for or quantify the risk of NP events with SINGULAIR use. Because of the risk of NP events, the benefits of SINGULAIR may not outweigh the risks in some patients, particularly when the symptoms of disease may be mild and adequately treated with alternative therapies. Reserve use of SINGULAIR for patients with allergic rhinitis who have an inadequate response or intolerance to alternative therapies . In patients with asthma or exercise-induced bronchoconstriction, consider the benefits and risks before prescribing SINGULAIR. Discuss the benefits and risks of SINGULAIR use with patients and caregivers when prescribing SINGULAIR. Advise patients and/or caregivers to be alert for changes in behavior or for new NP symptoms when taking SINGULAIR. If changes in behavior are observed, or if new NP symptoms or suicidal thoughts and/or behavior occur, advise patients to discontinue SINGULAIR and contact a healthcare provider immediately. In many cases, symptoms resolved after stopping SINGULAIR therapy; however, in some cases symptoms persisted after discontinuation of SINGULAIR. Therefore, continue to monitor and provide supportive care until symptoms resolve. Re-evaluate the benefits and risks of restarting treatment with SINGULAIR if such events occur

Acute Asthma SINGULAIR is not indicated for use in the reversal of bronchospasm in acute asthma attacks, including status asthmaticus. Patients should be advised to have appropriate rescue medication available. Therapy with SINGULAIR can be continued during acute exacerbations of asthma. Patients who have exacerbations of asthma after exercise should have available for rescue a short-acting inhaled β-agonist

Concomitant Corticosteroid Use While the dose of inhaled corticosteroid may be reduced gradually under medical supervision, SINGULAIR should not be abruptly substituted for inhaled or oral corticosteroids

Aspirin Sensitivity Patients with known aspirin sensitivity should continue avoidance of aspirin or non-steroidal anti-inflammatory agents while taking SINGULAIR. Although SINGULAIR is effective in improving airway function in asthmatics with documented aspirin sensitivity, it has not been shown to truncate bronchoconstrictor response to aspirin and other non-steroidal anti-inflammatory drugs in aspirin-sensitive asthmatic patients

Eosinophilic Conditions Patients with asthma on therapy with SINGULAIR may present with systemic eosinophilia, sometimes presenting with clinical features of vasculitis consistent with Churg-Strauss syndrome, a condition which is often treated with systemic corticosteroid therapy. These events have been sometimes associated with the reduction of oral corticosteroid therapy. Physicians should be alert to eosinophilia, vasculitic rash, worsening pulmonary symptoms, cardiac complications, and/or neuropathy presenting in their patients. A causal association between SINGULAIR and these underlying conditions has not been established

Risk in Patients with Phenylketonuria SINGULAIR contains aspartame, a source of phenylalanine. Phenylalanine can be harmful to patients with phenylketonuria (PKU). Each 4 mg and 5 mg chewable tablet contains 0.674 mg and 0.842 mg of phenylalanine, respectively. Before prescribing SINGULAIR to a patient with PKU, consider the combined daily amount of phenylalanine from all sources, including SINGULAIR.

No dose adjustment is needed when SINGULAIR is co-administered with theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin, gemfibrozil, itraconazole, thyroid hormones, sedative hypnotics, non-steroidal anti-inflammatory agents, benzodiazepines, decongestants, and Cytochrome P450 (CYP) enzyme inducers .