montelukast, Singulair

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GENERIC NAME: montelukast

BRAND NAME: Singulair

DRUG CLASS AND MECHANISM: Montelukast is an oral leukotriene receptor antagonist that is used for the treatment of asthma and seasonal allergic rhinitis (hay fever). Leukotrienes are a group of naturally occurring chemicals in the body that promote inflammation in asthma and seasonal allergic rhinitis and in other diseases in which inflammation is important (such as allergy). They are formed by cells, released, and then bound to other cells that cause inflammation. It is the binding to other cells that stimulates the cells to cause inflammation. Montelukast works in a manner similar to zafirlukast (Accolate), blocking the binding of some leukotrienes to the cells that cause inflammation. Unlike zafirlukast, montelukast does not inhibit CYP2C9 or CYP3A4, two enzymes in the liver that are important in breaking down and eliminating many drugs. Therefore, unlike zafirlukast, montelukast is not expected to affect the elimination of other drugs. The safety and effectiveness of montelukast has been demonstrated in children as young as 6 months of age. It was approved by the FDA in 1998.

GENERIC AVAILABLE: No

PRESCRIPTION: Yes

PREPARATIONS: Tablets: 10 mg. Chewable tablets: 4 and 5 mg.

STORAGE: Tablets should be stored at room temperature, 15-30 C (59-86 F).

PRESCRIBED FOR: Montelukast is used for the treatment of asthma, seasonal allergic rhinitis, and prevention of exercise induced bronchospasm (narrowing of airways). Montelukast begins working after 3 to 14 days of therapy; It should not be used for the treatment of an acute asthmatic attack.

DOSING: The recommended dose of montelukast in adults is 10 mg daily for treating asthma and allergic rhinitis and 10 mg two hours before exercising for prevention of exercise induced bronchospasm. Montelukast should be taken in the evening with or without food when used for asthma or allergic rhinitis. The 4 and 5 mg tablets are used in children.

DRUG INTERACTIONS: Phenobarbital, rifampin, and carbamazepine (Tegretol, Tegretol XR, Equertro, Carbatrol) may decrease blood concentrations of montelukast. This may reduce the effect of montelukast.

PREGNANCY: Montelukast crosses the placenta into the fetus following oral administration to animals, but there have been no adequate studies in pregnant women to determine the effects on the fetus. Physicians may prescribe zafirlukast during pregnancy if it is felt that its benefits outweigh the potential but unknown risks to the fetus.

NURSING MOTHERS: Studies in animals have shown that montelukast is excreted in milk; however, it is not known if montelukast is secreted into breast milk in humans.

SIDE EFFECTS: The most common side effects with montelukast are headache, dizziness, abdominal pain, sore throat, and rhinitis (inflammation of the inner lining of the nose). Wheezing, cough, rash, restlessness, tremor, and nausea may also occur. Elevated liver enzymes, suicidal behavior, fluid retention, depression, and hallucinations have also been reported.

Reference: FDA Prescribing Information


Last Editorial Review: 3/19/2012




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