Drug interactions
Diltiazem + Nirmatrelvir
Severity: Moderate
Diltiazem and Nirmatrelvir: moderate 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
Nirmatrelvir is given with ritonavir, a potent CYP3A4 inhibitor, which can substantially raise diltiazem concentrations. This may cause excessive bradycardia, AV conduction block, hypotension and edema.
What this interaction means in plain words
Diltiazem and Nirmatrelvir can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Diltiazem belongs to Cardiovascular; Nirmatrelvir belongs to Anti Virals.
Why it happens
Ritonavir-boosted nirmatrelvir inhibits CYP3A4, reducing diltiazem metabolism.
What to do
Monitor heart rate and blood pressure during the 5-day course and for a few days afterwards. Consider a temporary diltiazem dose reduction if symptomatic bradycardia or hypotension occurs.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Nirmatrelvir
- Alfuzosin + Nirmatrelvir Contraindicated
- Amiodarone + Nirmatrelvir Contraindicated
- Apalutamide + Nirmatrelvir Contraindicated
- Carbamazepine + Nirmatrelvir Contraindicated
- Colchicine + Nirmatrelvir Contraindicated
- Dronedarone + Nirmatrelvir Contraindicated
Frequently asked questions
Can I take Diltiazem with Nirmatrelvir?
MediHelp rates the interaction as moderate. Diltiazem and Nirmatrelvir can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Nirmatrelvir is given with ritonavir, a potent CYP3A4 inhibitor, which can substantially raise diltiazem concentrations. This may cause excessive bradycardia, AV conduction block, hypotension and edema.
How serious is the interaction between Diltiazem and Nirmatrelvir?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor heart rate and blood pressure during the 5-day course and for a few days afterwards. Consider a temporary diltiazem dose reduction if symptomatic bradycardia or hypotension occurs.
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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