Drug interactions
Montelukast + Zafirlukast
Severity: Minor
Montelukast and Zafirlukast: minor interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Both are leukotriene receptor antagonists with overlapping therapeutic action and no established benefit from combining them. Zafirlukast may slightly affect montelukast clearance through CYP enzymes, but this is of little importance.
What this interaction means in plain words
Montelukast and Zafirlukast have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Montelukast belongs to Respiratory; Zafirlukast belongs to Respiratory.
Why it happens
Possible weak CYP3A4 or CYP2C9 inhibition by zafirlukast; the drugs also duplicate pharmacologic action.
What to do
Avoid using both agents together because it is therapeutically redundant. Choose one leukotriene antagonist.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Zafirlukast
- Pimozide + Zafirlukast Contraindicated
- Lomitapide + Zafirlukast Major
- Nilotinib + Zafirlukast Major
- Warfarin + Zafirlukast Major
- Apalutamide + Zafirlukast Moderate
- Carbamazepine + Zafirlukast Moderate
Other interactions of Montelukast
- Apalutamide + Montelukast Moderate
- Carbamazepine + Montelukast Moderate
- Deferasirox + Montelukast Moderate
- Enzalutamide + Montelukast Moderate
- Fosphenytoin + Montelukast Moderate
- Gemfibrozil + Montelukast Moderate
Frequently asked questions
Can I take Montelukast with Zafirlukast?
MediHelp rates the interaction as minor. Montelukast and Zafirlukast have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Both are leukotriene receptor antagonists with overlapping therapeutic action and no established benefit from combining them. Zafirlukast may slightly affect montelukast clearance through CYP enzymes, but this is of little importance.
How serious is the interaction between Montelukast and Zafirlukast?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid using both agents together because it is therapeutically redundant. Choose one leukotriene antagonist.
What other medicines interact with Zafirlukast?
MediHelp also lists interactions of Zafirlukast with, for example, Pimozide, Lomitapide, Nilotinib. The full list is on the Zafirlukast page.
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