Drug interactions
Losartan + Zafirlukast
Severity: Minor
Losartan 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
Zafirlukast inhibits CYP2C9, which converts losartan to its active metabolite E-3174. This could reduce the antihypertensive effect, although the clinical importance has not been established.
What this interaction means in plain words
Losartan 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.
Losartan belongs to Cardiovascular; Zafirlukast belongs to Respiratory.
Why it happens
Inhibition of CYP2C9-mediated conversion of losartan to E-3174 by zafirlukast.
What to do
Monitor blood pressure when zafirlukast is started or stopped. Titrate the losartan dose to response if control worsens.
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 Losartan
- Aliskiren + Losartan Contraindicated
- Losartan + Sparsentan Contraindicated
- Amifostine + Losartan Major
- Amiloride + Losartan Major
- Amlodipine-benazepril + Losartan Major
- Amlodipine-hydrochlorothiazide-valsartan + Losartan Major
Frequently asked questions
Can I take Losartan with Zafirlukast?
MediHelp rates the interaction as minor. Losartan 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. Zafirlukast inhibits CYP2C9, which converts losartan to its active metabolite E-3174. This could reduce the antihypertensive effect, although the clinical importance has not been established.
How serious is the interaction between Losartan 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: Monitor blood pressure when zafirlukast is started or stopped. Titrate the losartan dose to response if control worsens.
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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