Drug interactions
Carvedilol + Diltiazem
Severity: Major
Carvedilol and Diltiazem: major 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
Diltiazem slows AV conduction and sinus rate, and carvedilol adds beta-blockade, so bradycardia, AV block and hypotension can occur. Diltiazem also inhibits CYP3A4 and CYP2D6 and may raise carvedilol exposure.
What this interaction means in plain words
Carvedilol 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.
Carvedilol belongs to Cardiovascular; Diltiazem belongs to Cardiovascular.
Why it happens
Additive negative chronotropic and dromotropic effects, plus diltiazem inhibition of carvedilol metabolism.
What to do
Monitor heart rate, ECG and blood pressure closely, particularly at initiation and after dose changes. Reduce the carvedilol dose if bradycardia or hypotension occurs, and avoid the combination in patients with conduction disease or reduced ventricular function.
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 Carvedilol
Other interactions of Diltiazem
- Diltiazem + Flibanserin Contraindicated
- Diltiazem + Ivabradine Contraindicated
- Diltiazem + Lomitapide Contraindicated
- Diltiazem + Lonafarnib Contraindicated
- Acebutolol + Diltiazem Major
- Alfentanil + Diltiazem Major
Frequently asked questions
Can I take Carvedilol with Diltiazem?
MediHelp rates the interaction as major. Carvedilol 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. Diltiazem slows AV conduction and sinus rate, and carvedilol adds beta-blockade, so bradycardia, AV block and hypotension can occur. Diltiazem also inhibits CYP3A4 and CYP2D6 and may raise carvedilol exposure.
How serious is the interaction between Carvedilol 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: Monitor heart rate, ECG and blood pressure closely, particularly at initiation and after dose changes. Reduce the carvedilol dose if bradycardia or hypotension occurs, and avoid the combination in patients with conduction disease or reduced ventricular function.
What other medicines interact with Carvedilol?
MediHelp also lists interactions of Carvedilol with, for example, Amifostine, Amiodarone, Arformoterol. The full list is on the Carvedilol page.
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