Drug interactions
Diltiazem + Penbutolol
Severity: Major
Diltiazem and Penbutolol: 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
Combining a beta-blocker with diltiazem can cause additive bradycardia, AV block, hypotension and reduced contractility. The risk is greatest in older patients and those with conduction disease or heart failure.
What this interaction means in plain words
Diltiazem and Penbutolol 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.
Why it happens
Additive negative chronotropic, dromotropic and inotropic effects of beta blockade and non-dihydropyridine calcium channel blockade.
What to do
Monitor heart rate, ECG and blood pressure closely, particularly at initiation. Avoid in patients with sinus node or AV nodal 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 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 Diltiazem with Penbutolol?
MediHelp rates the interaction as major. Diltiazem and Penbutolol 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. Combining a beta-blocker with diltiazem can cause additive bradycardia, AV block, hypotension and reduced contractility. The risk is greatest in older patients and those with conduction disease or heart failure.
How serious is the interaction between Diltiazem and Penbutolol?
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. Avoid in patients with sinus node or AV nodal disease or reduced ventricular function.
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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