Drug interactions
Avapritinib + Diltiazem
Severity: Major
Avapritinib and Diltiazem: major interaction.
Last updated Sources: Health Canada product monograph
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
Avapritinib is metabolized mainly by CYP3A4, and diltiazem is a moderate CYP3A4 inhibitor. Raised avapritinib exposure can increase adverse effects such as cognitive impairment, intracranial hemorrhage and edema.
What this interaction means in plain words
Avapritinib and Diltiazem 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.
Avapritinib belongs to Oncology; Diltiazem belongs to Cardiovascular.
Why it happens
Diltiazem inhibits CYP3A4 and reduces avapritinib clearance.
What to do
Avoid concurrent use and choose an alternative to diltiazem. If it cannot be avoided, reduce the avapritinib starting dose per labeling and monitor for adverse effects.
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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References
Other interactions of Diltiazem
- Diltiazem + Flibanserin Contraindicated
- Diltiazem + Ivabradine Contraindicated
- Diltiazem + Lomitapide Contraindicated
- Diltiazem + Lonafarnib Contraindicated
- Acebutolol + Diltiazem Major
- Alfentanil + Diltiazem Major
Other interactions of Avapritinib
Frequently asked questions
Can I take Avapritinib with Diltiazem?
MediHelp rates the interaction as major. Avapritinib and Diltiazem 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. Avapritinib is metabolized mainly by CYP3A4, and diltiazem is a moderate CYP3A4 inhibitor. Raised avapritinib exposure can increase adverse effects such as cognitive impairment, intracranial hemorrhage and edema.
How serious is the interaction between Avapritinib and Diltiazem?
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 concurrent use and choose an alternative to diltiazem. If it cannot be avoided, reduce the avapritinib starting dose per labeling and monitor for adverse effects.
What other medicines interact with Diltiazem?
MediHelp also lists interactions of Diltiazem with, for example, Flibanserin, Ivabradine, Lomitapide. The full list is on the Diltiazem page.
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