Oxybutynin and Ketoconazole Interaction
Drug interaction information between Oxybutynin and Ketoconazole.
Oxybutynin and Ketoconazole have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Oxybutynin 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 enzyme that breaks down oxybutynin, which can cause the amount of oxybutynin in your body to double.
FDA Label Information
Mean oxybutynin chloride plasma concentrations were approximately 2 fold higher when Oxybutynin chloride extended-release tablets were administered with ketoconazole, a potent CYP3A4 inhibitor. (7) Co-administration with strong cytochrome P450 (CYP) 3A4 inhibitors (e.g., ketoconazole) increases the systemic exposure of oxybutynin.
Oxybutynin Also Interacts With
- Erythromycin minor
- Clarithromycin minor
- Itraconazole minor
- Metoclopramide minor
- Carbamazepine 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 Oxybutynin + 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 Oxybutynin's 7. In the minor band specifically: Oxybutynin has 7 (also Erythromycin, Clarithromycin, Itraconazole, Metoclopramide); Ketoconazole has 85 (also Abiraterone, Acetaminophen/Oxycodone, Alosetron, Amphotericin B).
What mechanism field is on file for Oxybutynin and Ketoconazole?
Ketoconazole blocks the enzyme that breaks down oxybutynin, which can cause the amount of oxybutynin in your body to double.
Ketoconazole carries more major-labeled pairs than Oxybutynin
SPL source-record counts only. This page's band is minor · classes on file: Oxybutynin (Anticholinergic / Antispasmodic); Ketoconazole (Azole Antifungal).
Ketoconazole has 6 major-labeled pairs vs Oxybutynin's 0. This page itself is in the minor band, not the major band.
0 major · 0 moderate · 7 minor · 7 total
- Other minor peers for Oxybutynin
- Erythromycin
- Clarithromycin
- Itraconazole
- Metoclopramide
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.