Hydralazine and Tadalafil Interaction
Drug interaction information between Hydralazine and Tadalafil.
Hydralazine and Tadalafil have a documented major interaction in FDA labeling.
FDA drug labeling documents a major-severity interaction between Hydralazine and Tadalafil. 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
These medicines both lower blood pressure in a similar way, and using them at the same time can cause a severe and unsafe drop in blood pressure.
FDA Label Information
7 DRUG INTERACTIONS 7.1 Phosphodiesterase Inhibitors BiDil is contraindicated in patients who are using a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5), PDE5 inhibitors such as avanafil, sildenafil, vardenafil, and tadalafil have been shown to potentiate the hypotensive effects of organic nitrates.
Tadalafil Also Interacts With
- Clarithromycin moderate
- Nirmatrelvir/Ritonavir moderate
- Amlodipine minor
- Metoprolol minor
- Tamsulosin minor
Frequently Asked Questions
What SPL severity band is on file for Hydralazine/Isosorbide Dinitrate + Tadalafil?
Compiled FDA labeling labels this pair major. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Tadalafil has 25 labeled pairs on file vs Hydralazine's 2. In the major band specifically: Hydralazine has 2 (also Sildenafil); Tadalafil has 1.
What mechanism field is on file for Hydralazine/Isosorbide Dinitrate and Tadalafil?
These medicines both lower blood pressure in a similar way, and using them at the same time can cause a severe and unsafe drop in blood pressure.
Hydralazine carries more major-labeled pairs than Tadalafil
SPL source-record counts only. This page's band is major · classes on file: Hydralazine (Vasodilator / Nitrate Combination); Tadalafil (PDE5 Inhibitor).
Hydralazine has 2 major-labeled pairs vs Tadalafil's 1.
1 major · 2 moderate · 22 minor · 25 total
Tadalafil has no other major-band peer in this dataset besides Hydralazine.
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.