Drug interactions
Pimozide + Terbinafine
Severity: Major
Pimozide and Terbinafine: major 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
Pimozide is metabolized by CYP2D6 and CYP3A4 and has a narrow margin for QT prolongation. Terbinafine may raise pimozide concentrations and increase the risk of QT prolongation and torsades de pointes.
What this interaction means in plain words
Pimozide and Terbinafine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Pimozide belongs to Central Nervous System; Terbinafine belongs to Anti Fungals.
Why it happens
Terbinafine inhibits CYP2D6, reducing pimozide clearance and increasing its QT-prolonging exposure.
What to do
Avoid the combination where possible and use an alternative antifungal. If it must be used, obtain a baseline and follow-up ECG and consider lowering the pimozide dose.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Terbinafine
- Terbinafine + Thioridazine Contraindicated
- Desipramine + Terbinafine Major
- Eliglustat + Terbinafine Major
- Flecainide + Terbinafine Major
- Imipramine + Terbinafine Major
- Maprotiline + Terbinafine Major
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 Terbinafine?
MediHelp rates the interaction as major. Pimozide and Terbinafine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Pimozide is metabolized by CYP2D6 and CYP3A4 and has a narrow margin for QT prolongation. Terbinafine may raise pimozide concentrations and increase the risk of QT prolongation and torsades de pointes.
How serious is the interaction between Pimozide and Terbinafine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible and use an alternative antifungal. If it must be used, obtain a baseline and follow-up ECG and consider lowering the pimozide dose.
What other medicines interact with Terbinafine?
MediHelp also lists interactions of Terbinafine with, for example, Thioridazine, Desipramine, Eliglustat. The full list is on the Terbinafine page.
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