Drug interactions
Erythromycin base + Pimozide
Severity: Contraindicated
Erythromycin base and Pimozide: contraindicated interaction.
Last updated Sources: US FDA label
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
Erythromycin inhibits CYP3A4 and raises pimozide concentrations, and it also prolongs the QT interval itself. Together they markedly increase the risk of torsades de pointes and sudden death.
What this interaction means in plain words
Erythromycin base and Pimozide 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.
Why it happens
Erythromycin inhibits CYP3A4-mediated pimozide metabolism and adds its own QT-prolonging effect.
What to do
Do not co-administer. Use an antibiotic that does not inhibit CYP3A4 or prolong QT, such as a beta-lactam.
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?
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References
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 Erythromycin base with Pimozide?
MediHelp rates the interaction as contraindicated. Erythromycin base and Pimozide 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. Erythromycin inhibits CYP3A4 and raises pimozide concentrations, and it also prolongs the QT interval itself. Together they markedly increase the risk of torsades de pointes and sudden death.
How serious is the interaction between Erythromycin base and Pimozide?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Do not co-administer. Use an antibiotic that does not inhibit CYP3A4 or prolong QT, such as a beta-lactam.
What other medicines interact with Pimozide?
MediHelp also lists interactions of Pimozide with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Pimozide page.
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