Propranolol and Diltiazem Interaction
Drug interaction information between Propranolol and Diltiazem.
Propranolol and Diltiazem have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Propranolol and Diltiazem. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Both drugs slow down the heart and lower blood pressure. Taking them together can cause the heart to beat too slowly or lead to heart failure.
FDA Label Information
Co-administration of propranolol and diltiazem in patients with cardiac disease has been associated with bradycardia, hypotension, high-degree heart block, and heart failure.
Propranolol Also Interacts With
- Clonidine minor
- Warfarin minor
- Verapamil minor
- Doxazosin minor
- Haloperidol minor
Diltiazem Also Interacts With
- Ezetimibe major
- Ezetimibe/Simvastatin major
- Simvastatin major
- Theophylline major
- Rifampin moderate
Frequently Asked Questions
What SPL severity band is on file for Propranolol + Diltiazem?
Compiled FDA labeling labels this pair minor. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Diltiazem has 46 labeled pairs on file vs Propranolol's 44. In the minor band specifically: Propranolol has 44 (also Clonidine, Warfarin, Verapamil, Doxazosin); Diltiazem has 35 (also Buspirone, Pravastatin, Lovastatin, Cyclosporine).
What mechanism field is on file for Propranolol and Diltiazem?
Both drugs slow down the heart and lower blood pressure. Taking them together can cause the heart to beat too slowly or lead to heart failure.
Diltiazem carries more major-labeled pairs than Propranolol
SPL source-record counts only. This page's band is minor · classes on file: Propranolol (Non-Selective Beta-Blocker); Diltiazem (Calcium Channel Blocker).
Diltiazem has 4 major-labeled pairs vs Propranolol's 0. This page itself is in the minor band, not the major band.
0 major · 0 moderate · 44 minor · 44 total
4 major · 7 moderate · 35 minor · 46 total
- Other minor peers for Diltiazem
- Buspirone
- Pravastatin
- Lovastatin
- Cyclosporine
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.