Drug interactions
Fosaprepitant + Zafirlukast
Severity: Minor
Fosaprepitant 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
Fosaprepitant is converted to aprepitant, a CYP3A4 substrate, and zafirlukast could marginally raise its levels. Aprepitant is well tolerated and a small increase is unlikely to matter.
What this interaction means in plain words
Fosaprepitant 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.
Fosaprepitant belongs to Gastrointestinal Tract; Zafirlukast belongs to Respiratory.
Why it happens
Weak CYP3A4 inhibition by zafirlukast reduces aprepitant clearance.
What to do
No adjustment needed; monitor for headache, fatigue or gastrointestinal effects.
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 Fosaprepitant
- Flibanserin + Fosaprepitant Contraindicated
- Fosaprepitant + Pimozide Contraindicated
- Alprazolam + Fosaprepitant Moderate
- Amiodarone + Fosaprepitant Moderate
- Amobarbital + Fosaprepitant Moderate
- Apalutamide + Fosaprepitant Moderate
Frequently asked questions
Can I take Fosaprepitant with Zafirlukast?
MediHelp rates the interaction as minor. Fosaprepitant 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. Fosaprepitant is converted to aprepitant, a CYP3A4 substrate, and zafirlukast could marginally raise its levels. Aprepitant is well tolerated and a small increase is unlikely to matter.
How serious is the interaction between Fosaprepitant 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: No adjustment needed; monitor for headache, fatigue or gastrointestinal effects.
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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