Does Ketoconazole Interact With Oxybutynin?

Name: Does Ketoconazole Interact With Oxybutynin?
Creator: OmniRx Health

Mean oxybutynin chloride plasma concentrations were approximately 2 fold higher when Oxybutynin chloride extended-release tablets were administered with ketoconazole, a potent CYP3A4 inhibitor.

Reviewed by the OmniRx Health clinical team•Last reviewed Jul 4, 2026

Severity: Minor

Severity basis: drug interactions section. Combining Ketoconazole (Azole antifungal (strong CYP3A4 inhibitor)) and Oxybutynin (Anticholinergic (overactive bladder)) is classified as a minor interaction.

What to Do

This is generally a minor interaction, but review it with your pharmacist to be sure it is safe for you.

How This Interaction Works

Interactions like this one can happen when two medicines have overlapping effects, or when one changes how the other is absorbed, broken down, or cleared from the body. Ketoconazole is a azole antifungal (strong cyp3a4 inhibitor) and Oxybutynin is a anticholinergic (overactive bladder); together they are documented as a minor interaction. How much this matters depends on your dose, your other medications, and your overall health.

If You Take Both Medications

If you have been prescribed both Ketoconazole and Oxybutynin, do not start, stop, or change either medication on your own — some medicines are unsafe to stop suddenly. Tell your prescriber and pharmacist that you take both so they can decide whether the combination is right for you, adjust the dose, monitor you more closely, or suggest an alternative.

From the FDA Label

Mean oxybutynin chloride plasma concentrations were approximately 2 fold higher when Oxybutynin chloride extended-release tablets were administered with ketoconazole, a potent CYP3A4 inhibitor.

Source: FDA structured product labeling (set_id 02ff3be7-fc5c-4b91-8c67-ecdf6e19c42a).

Ketoconazole

Azole antifungal (strong CYP3A4 inhibitor)

Brands: Nizoral

View Ketoconazole safety profile

Oxybutynin

Anticholinergic (overactive bladder)

Brands: Ditropan, Oxytrol

View Oxybutynin safety profile

Check these against your full medication list in our free Interaction Checker

Frequently Asked Questions

Can you take Ketoconazole and Oxybutynin together?

Ketoconazole and Oxybutynin have a documented minor interaction. This is generally a minor interaction, but review it with your pharmacist to be sure it is safe for you.

How serious is the Ketoconazole and Oxybutynin interaction?

It is classified as a minor interaction, based on the FDA label's drug interactions section. A minor interaction is usually limited in effect but is still worth discussing with your care team.

What should I do if I'm taking both Ketoconazole and Oxybutynin?

This information is educational — not medical advice.

This page is provided for general educational purposes and summarizes publicly available data from sources such as the U.S. Food & Drug Administration. It is not a substitute for the judgment of a licensed clinician and should not be used to start, stop, or change any medication. It may be incomplete or out of date, and individual circumstances vary. Always talk with your prescriber or pharmacist about your specific medications and health conditions. If you think you may have a medical emergency, call 911.

Questions About Your Medications?

A licensed OmniRx provider can review your full medication list and help you understand what's safe for you — no office visit required.

Other Ketoconazole Interactions

Other Oxybutynin Interactions

Sources & References

Learn more about where our data comes from and how we write and review medical content.