
Montelukast works in a manner similar to zafirlukast (Accolate), blocking the binding of some leukotrienes. 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.

DRUG INTERACTIONS: Phenobarbital increases the blood concentration of montelukast by about 40%. Rifampin may have the same effect. Therefore, the dose of montelukast may need to be reduced when given concurrently with these drugs.

The medication comes in tablet form and is taken by mouth once a day (in the evening, if used for asthma), although some people take it only before exercising (for treating exercise-induced asthma).

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