Diltiazem and Labetalol interaction
Diltiazem and Labetalol: 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 Labetalol (Labetalol Hydrochloride) label · effective 2025-12-19
IV administration of non-dihydropyridine calcium-channel antagonists (e.g., verapamil) Hypersensitivity reactions, including anaphylaxis, to labetalol Bronchial asthma ( 4 )
Calcium Channel Blockers Coadministration of labetalol HCl with non-dihydropyrindine calcium-channel antagonists (e.g., verapamil) is contraindicated [see Contraindications (4) ].
Avoid the use of labetalol in patients receiving calcium-channel antagonists.
From the Diltiazem (Cardizem LA) label · effective 2025-11-11
Concomitant use of diltiazem with beta-blockers or digitalis may result in additive effects on cardiac conduction.
• Beta-blockers, digitalis, and other agents known to impair cardiac contractility and conduction may increase risk for hypotension, bradycardia, and heart failure.
Experience with the use of diltiazem in combination with beta-blockers in patients with impaired ventricular function is limited.
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.