Venlafaxine and Ketoconazole Interaction
Drug interaction information between Venlafaxine and Ketoconazole.
Venlafaxine and Ketoconazole have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Venlafaxine 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 blocks the enzymes that break down venlafaxine, which causes the level of the medicine to rise in your blood.
FDA Label Information
Ketoconazole A pharmacokinetic study with ketoconazole 100 mg b.i.d. with a single dose of venlafaxine 50 mg in extensive metabolizers (EM; n = 14) and 25 mg in poor metabolizers (PM; n = 6) of CYP2D6 resulted in higher plasma concentrations of both venlafaxine and O-desvenlafaxine (ODV) in most subjects following administration of ketoconazole.
Venlafaxine Also Interacts With
- Aspirin moderate
- Phenelzine moderate
- Metoprolol minor
- Fluoxetine minor
- Alprazolam 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 Venlafaxine + 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 Venlafaxine's 22. In the minor band specifically: Venlafaxine has 20 (also Metoprolol, Fluoxetine, Alprazolam, Warfarin); Ketoconazole has 85 (also Abiraterone, Acetaminophen/Oxycodone, Alosetron, Amphotericin B).
What mechanism field is on file for Venlafaxine and Ketoconazole?
Ketoconazole blocks the enzymes that break down venlafaxine, which causes the level of the medicine to rise in your blood.
Ketoconazole carries more major-labeled pairs than Venlafaxine
SPL source-record counts only. This page's band is minor · classes on file: Venlafaxine (Serotonin-Norepinephrine Reuptake Inhibitor (SNRI)); Ketoconazole (Azole Antifungal).
Ketoconazole has 6 major-labeled pairs vs Venlafaxine's 0. This page itself is in the minor band, not the major band.
0 major · 2 moderate · 20 minor · 22 total
- Other minor peers for Venlafaxine
- Metoprolol
- Fluoxetine
- Alprazolam
- Warfarin
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.