Zafirlukast

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, and Foods
(for details about the summarized interactions, read the full article)

Avoid: Reduced drug absorption/bioavailability—Avoid these supplements when taking this medication since the supplement may decrease the absorption and/or activity of the medication in the body.	Food
Avoid: Adverse interaction—Avoid these supplements when taking this medication because taking them together may cause undesirable or dangerous results.	Willow*
Depletion or interference	None known
Side effect reduction/prevention	None known
Supportive interaction	None known

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 and Other Compounds

Food
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.

References

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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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires March 2005.