Diltiazem and Propranolol interaction
Diltiazem and Propranolol: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Diltiazem (DILTIAZEM HYDROCHLORIDE in SODIUM CHLORIDE) label · effective 2025-04-15
• Concomitant administration with IV beta-blockers.
Beta-blockers Increased risk of bradycardia, AV block, and depression of contractility.
Beta-blocker may need to be decreased [see Warnings and Precautions (5.1, 5.2)].
• Beta-Blockers: Monitor for bradycardia, AV block, and depression of contractility.
From the Propranolol (InnoPran XL) label · effective 2026-08-27
The concomitant use of beta-adrenergic blockers and non-dihydropyridine calcium channel blockers (e.g., verapamil and diltiazem), digoxin or clonidine increases the risk of significant bradycardia.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.