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Montelukast Sodium

Pronouncation: (mon-te-LOO-kast SOE-dee-um)
Class: Leukotriene receptor antagonist

Trade Names:
Singulair
- Tablets 10 mg
- Tablets, chewable 4 mg
- Tablets, chewable 5 mg
- Granules 4 mg/packet

Pharmacology

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Binds to cysteinyl leukotriene receptor 1 in the upper and lower airways to prevent leukotriene-mediated effects associated with asthma and allergic rhinitis.

Pharmacokinetics

Absorption

T _max is 3 to 4 h and bioavailability is 64% for 10 mg oral tablet. T _max is 2 to 2.5 h and bioavailability is 73% (63% if taken with food) for 5 mg chewable tablet. T _max is 2 h for 4 mg chewable tablet. The 4 mg granule formulation is bioequivalent to the 4 mg chewable tablet when administered in fasted state. Administration of granules with high-fat meal does not affect AUC but prolongs T _max to 6.4 h.

Distribution

Protein binding more than 99%. Vd is 8 to 11 L/kg.

Metabolism

Extensively metabolized; plasma concentrations of metabolites are undetectable at steady state. CYP-450 3A4 and 2C9 are involved in metabolism.

Elimination

Plasma Cl averages 45 mL/min and mean plasma t _½ is 2.7 to 5.5 h; 86% recovered in feces and less than 0.2% in urine.

Special Populations

Renal Function Impairment

Because montelukast and its metabolites are not excreted in the urine, pharmacokinetics were not evaluated in renal function impairment.

Hepatic Function Impairment

AUC increased 41% and t _½ was prolonged to 7.4 h in patients with mild to moderate hepatic function impairment.

Elderly

Plasma t _½ is slightly longer.

Gender

Pharmacokinetics are similar in males and females.

Race

Differences have not been studied.

Indications and Usage

Prophylaxis and chronic treatment of asthma in patients 12 mo of age and older; relief of symptoms of seasonal allergic rhinitis in patients 2 yr of age and older; relief of symptoms of perennial allergic rhinitis in patients 6 mo of age and older.

Prevention of exercise-induced bronchoconstriction (EIB) in patients 15 yr of age and older.

Unlabeled Uses

Chronic urticaria, atopic dermatitis.

Contraindications

Standard considerations.

Dosage and Administration

Asthma
Adults and children 12 mo of age and older

PO Should be taken once daily.

Adults and adolescents 15 yr of age and older

10 mg daily.

Children 6 to 14 yr of age

5 mg daily.

Children 12 mo to 5 yr of age

4 mg daily.

EIB
Adults and children 15 yr of age and older

PO 10 mg 2 h prior to exercise. An additional dose should not be taken within 24 h of the previous dose.

Perennial Allergic Rhinitis
Adults and Adolescents 15 yr of age and older

PO 10 mg daily.

Children 6 to 14 yr of age

PO 5 mg once daily.

Children 6 mo to 5 yr of age

PO 4 mg once daily.

Seasonal Allergic Rhinitis
Adults and children 2 yr of age and older

PO Should be taken once daily.

Adults and adolescents 15 yr of age and older

PO 10 mg daily.

Children 6 to 14 yr of age

PO 5 mg daily.

Children 2 to 5 yr of age

PO 4 mg daily.

General Advice

Patients taking a daily dose for a particular indication, including chronic asthma, should not take an additional dose to prevent EIB.

Patients with both asthma and allergic rhinitis should take only 1 tablet daily in the evening.

Oral granules

Do not open packet containing granules until ready for use; the full dose must be administered within 15 min of opening packet.
Granules can be administered 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 (applesauce, carrots, rice, or ice cream only). If mixing with baby formula, breast milk, or food, do not prepare ahead of time or store for future use. Discard any unused portion.
Do not dissolve granules in any liquid other than baby formula or breast milk for administration; however, liquids can be taken subsequent to administration.

Storage/Stability

Store at controlled room temperature (59° to 86°F). Protect from moisture and light.

Drug Interactions

Phenobarbital, rifampin

May decrease montelukast levels.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Cardiovascular

Cardiac complications, palpitations (postmarketing).

CNS

Headache (18%); asthenia/fatigue, dizziness (2%); abnormal dreams, depression, drowsiness, hallucinations, insomnia, paraesthesia/hypoesthesia, psychomotor hyperactivity (including agitation, aggressive behavior, irritability, restlessness, and tremor), seizures (postmarketing).

Dermatologic

Atopic dermatitis, dermatitis, eczema, skin infection, urticaria (at least 2%); rash (2%); vasculitic rash (postmarketing).

EENT

Conjunctivitis, ear pain, myopia, otitis, pharyngitis, rhinorrhea, sinusitis, tonsillitis (at least 2%); nasal congestion (2%); epistaxis (at least 1%).

GI

Diarrhea, dyspepsia, gastroenteritis, laryngitis, nausea, tooth infection (at least 2%); dental pain, infectious gastroenteritis (2%); pancreatitis, vomiting (postmarketing).

Hematologic-Lymphatic

Bruising, eosinophilia, increased bleeding tendency (postmarketing).

Hepatic

Cholestatic hepatitis, hepatocellular liver-injury, mixed-pattern liver injury (postmarketing).

Lab Tests

ALT/AST increased (2%); pyuria (1%).

Musculoskeletal

Arthralgia, myalgia (including muscle cramps) (postmarketing).

Respiratory

Influenza (4%); cough (3%); acute bronchitis, pneumonia, upper respiratory tract infection, wheezing (at least 2%); worsening of pulmonary symptoms (postmarketing).

Miscellaneous

Abdominal pain (3%); fever, varicella, viral infection (at least 2%); trauma (1%); edema, hypersensitivity (including anaphylaxis, hepatic eosinophilic infiltration, pruritus, and urticaria) (postmarketing).

Precautions

Pregnancy

Category B .

Lactation

Undetermined.

Children

Safety and efficacy not established for treatment of asthma in patients younger than 12 mo of age. Safety and efficacy not established for treatment of allergic rhinitis in patients younger than 2 yr of age. Safety and efficacy not established for treatment of perennial allergic rhinitis in patients younger than 6 mo of age. Safety and efficacy not established for treatment of EIB in patients younger than 15 yr of age.

Acute asthma attacks

Do not use for reversal of bronchospasm in acute asthma attacks, including status asthmaticus.

Concurrent corticosteroids

Do not abruptly substitute montelukast for inhaled or oral corticosteroids.

Eosinophilic conditions

Systemic eosinophilia may occur, sometimes presenting with clinical features of vasculitis consistent with Churg-Strauss syndrome.

Exercise-induced asthma

Do not use montelukast as monotherapy for treatment and management of EIB.

Phenylketonuria

Montelukast chewable tablets contain phenylalanine.

Overdosage

Symptoms

Abdominal pain, headache, hyperkinesia, mydriasis, somnolence, thirst, vomiting.

Patient Information

Advise patient to read patient information leaflet before using the first time and to reread and check for new information with each refill.
Caution patient with asthma not to decrease the dose or stop taking any other asthma medications unless advised by health care provider.
Advise patient that montelukast can be taken without regard to meals, but to take with food if stomach upset occurs.
Advise patient with asthma or asthma and allergic rhinitis to take prescribed dose once daily in the evening.
Advise patient with allergic rhinitis to take prescribed dose once daily at a time that is convenient, but at about the same time each day.
Advise patient or caregiver using granules that packet containing granules should not be opened until ready for use and that the full dose must be administered within 15 min. Granules can be administered directly in the mouth, dissolved in 1 teaspoonful (5 mL) of cold or room temperature formula or breast milk, or mixed with a spoonful of cold or room temperature soft foods (applesauce, carrots, rice, or ice cream only). Caution patient or caregiver mixing granules with baby formula, breast milk, or food not to prepare ahead of time or store for future use. Instruct patient to discard any unused portion.
Caution patient with asthma that medication is not to be used to treat acute asthma attacks. Instruct patient to always have a short-acting beta-agonist available for acute treatment of asthma symptoms.
Instruct patient to take montelukast every day as prescribed, even when symptoms have been controlled.
Caution patient not to increase montelukast dose or frequency of use, but to notify health care provider if symptoms return or worsen, or, for patient with asthma, if the need for rescue medication increases, or if rescue medication does not seem to work as well.
Advise patient with EIB to use the usual regimen of beta-agonists as prophylaxis unless otherwise instructed by health care provider.
Advise patient with known aspirin sensitivity to continue avoidance of aspirin and NSAIDs while taking montelukast.