Drug interactions
Pimozide + Zafirlukast
Severity: Contraindicated
Pimozide and Zafirlukast: contraindicated 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 CYP3A4 and CYP2C9 and may raise pimozide concentrations. Pimozide has a narrow therapeutic index and elevated levels can cause QT prolongation and torsades de pointes.
What this interaction means in plain words
Pimozide and Zafirlukast are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Pimozide belongs to Central Nervous System; Zafirlukast belongs to Respiratory.
Why it happens
Zafirlukast inhibits CYP3A4 (and CYP2C9), reducing pimozide metabolism.
What to do
Avoid the combination and use an alternative asthma controller such as an inhaled corticosteroid or montelukast. If unavoidable, obtain ECG and electrolytes.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Pimozide and Zafirlukast, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
Other interactions of Zafirlukast
- Lomitapide + Zafirlukast Major
- Nilotinib + Zafirlukast Major
- Warfarin + Zafirlukast Major
- Apalutamide + Zafirlukast Moderate
- Carbamazepine + Zafirlukast Moderate
- Conivaptan + Zafirlukast Moderate
Other interactions of Pimozide
- Adagrasib + Pimozide Contraindicated
- Amiodarone + Pimozide Contraindicated
- Amisulpride + Pimozide Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amoxapine + Pimozide Contraindicated
- Anagrelide + Pimozide Contraindicated
Frequently asked questions
Can I take Pimozide with Zafirlukast?
MediHelp rates the interaction as contraindicated. Pimozide and Zafirlukast are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Zafirlukast inhibits CYP3A4 and CYP2C9 and may raise pimozide concentrations. Pimozide has a narrow therapeutic index and elevated levels can cause QT prolongation and torsades de pointes.
How serious is the interaction between Pimozide and Zafirlukast?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination and use an alternative asthma controller such as an inhaled corticosteroid or montelukast. If unavoidable, obtain ECG and electrolytes.
What other medicines interact with Zafirlukast?
MediHelp also lists interactions of Zafirlukast with, for example, Lomitapide, Nilotinib, Warfarin. The full list is on the Zafirlukast page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
