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Zafirlukast is used in the prevention and treatment of mild to severe asthma, seasonal allergic asthma, exercise-induced asthma, and aspirin-induced asthma. It belongs to a class of drugs called leukotriene-receptor antagonists (LTRA).

Summary of Interactions with Vitamins, Herbs, & Foods

dnicon_Beneficial May Be Beneficial: Depletion or interference—This medication may deplete these substances from the body or interfere with how they work; extra intake may help replenish them.


dnicon_Beneficial May Be Beneficial: Side effect reduction and/or prevention—These substances may help reduce the likelihood and/or severity of a potential side effect caused by the medication.


dnicon_Beneficial May Be Beneficial: Supportive interaction—These substances may help this medication work better.


dnicon_Avoid Avoid: Reduces drug effectiveness—When taking this medication, avoid these substances as they may decrease the medication's absorption and/or activity in the body.


dnicon_Avoid Avoid: Adverse interaction—When taking this medication, avoid these substances, as the combination may cause undesirable or dangerous interactions.

White Willow*

dnicon_Check Check: Explanation needed—When taking this medication, read the article details and discuss them with your doctor or pharmacist before taking these substances.


An asterisk (*) next to an item in the summary indicates that the interaction is supported only by weak, fragmentary, and/or contradictory scientific evidence.

Interactions Details

Interactions with Herbs

Willow  (Salix alba)

Willow bark contains salicin, a substance similar to aspirin. Research has shown that aspirin significantly increases blood levels of zafirlukast,1 which would increase the likelihood of side effects from zafirlukast. The same thing could theoretically happen if people took willow bark along with zafirlukast, although no studies have investigated this specific interaction. People may want to avoid combining willow bark with zafirlukast due to the possibility of increased side effects.

Interactions with Foods & Other Compounds


The ingestion of food along with zafirlukast can reduce the overall absorption of the drug by about 40%.2 Therefore, zafirlukast should be taken one hour before or two hours after a meal.


Common brand names:



1. Kelloway JS. Zafirlukast: the first leukotriene-receptor antagonist approved for the treatment of asthma. Ann Pharmacother 1997;31(9):1012–21.

2. Kelloway JS. Zafirlukast: the first leukotriene-receptor antagonist approved for the treatment of asthma. Ann Pharmacother 1997;31(9):1012–21.

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