Terbinafine and Ketoconazole Interaction
Drug interaction information between Terbinafine and Ketoconazole.
Terbinafine and Ketoconazole have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Terbinafine and Ketoconazole. 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
Ketoconazole stops the body from breaking down terbinafine, which can lead to much higher levels of terbinafine in your blood.
FDA Label Information
Based on this finding, it is likely that other inhibitors of both CYP2C9 and CYP3A4 (e.g., ketoconazole, amiodarone) may also lead to a substantial increase in the systemic exposure (C max and AUC) of terbinafine when concomitantly administered.
Terbinafine Also Interacts With
- Tamsulosin moderate
- Fluconazole minor
- Cyclosporine minor
- Trimethoprim minor
- Rifampin minor
Ketoconazole Also Interacts With
- Alfuzosin major
- Dronedarone major
- Ranolazine major
- Saxagliptin major
- Sildenafil major
Frequently Asked Questions
What SPL severity band is on file for Terbinafine + Ketoconazole?
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?
Ketoconazole has 113 labeled pairs on file vs Terbinafine's 17. In the minor band specifically: Terbinafine has 16 (also Fluconazole, Cyclosporine, Trimethoprim, Rifampin); Ketoconazole has 85 (also Abiraterone, Acetaminophen/Oxycodone, Alosetron, Amphotericin B).
What mechanism field is on file for Terbinafine and Ketoconazole?
Ketoconazole stops the body from breaking down terbinafine, which can lead to much higher levels of terbinafine in your blood.
Ketoconazole carries more major-labeled pairs than Terbinafine
SPL source-record counts only. This page's band is minor · classes on file: Terbinafine (Allylamine Antifungal); Ketoconazole (Azole Antifungal).
Ketoconazole has 6 major-labeled pairs vs Terbinafine's 0. This page itself is in the minor band, not the major band.
0 major · 1 moderate · 16 minor · 17 total
- Other minor peers for Terbinafine
- Fluconazole
- Cyclosporine
- Trimethoprim
- Rifampin
6 major · 22 moderate · 85 minor · 113 total
- Other minor peers for Ketoconazole
- Abiraterone
- Acetaminophen/Oxycodone
- Alosetron
- Amphotericin B
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.