Dexamethasone and Ketoconazole Interaction
Drug interaction information between Dexamethasone and Ketoconazole.
Dexamethasone and Ketoconazole have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Dexamethasone and Ketoconazole. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
Ketoconazole slows down how your body breaks down the steroid, which can cause the medicine to build up to high levels. This increases your risk of having serious side effects from the steroid.
What To Do
Your doctor may need to lower your steroid dose or watch you closely for side effects while you are taking both medicines.
FDA Label Information
Drugs which inhibit CYP 3A4 (e.g., ketoconazole, macrolide antibiotics such as erythromycin) have the potential to result in increased plasma concentrations of corticosteroids. Ketoconazole: Ketoconazole has been reported to decrease the metabolism of certain corticosteroids by up to 60%, leading to increased risk of corticosteroid side effects. In addition, ketoconazole alone can inhibit adrenal corticosteroid synthesis and may cause adrenal insufficiency during corticosteroid withdrawal.
Dexamethasone Also Interacts With
- Aspirin moderate
- Nirmatrelvir/Ritonavir moderate
- Warfarin minor
- Cyclosporine minor
- Hydrocortisone minor
Ketoconazole Also Interacts With
- Alfuzosin major
- Dronedarone major
- Ranolazine major
- Saxagliptin major
- Sildenafil major
Frequently Asked Questions
Can I take Dexamethasone and Ketoconazole together?
This is a moderate interaction. Your doctor may need to lower your steroid dose or watch you closely for side effects while you are taking both medicines.
How serious is the interaction between Dexamethasone and Ketoconazole?
This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.
Why do Dexamethasone and Ketoconazole interact?
Ketoconazole slows down how your body breaks down the steroid, which can cause the medicine to build up to high levels. This increases your risk of having serious side effects from the steroid.
Understanding the Dexamethasone and Ketoconazole Interaction
FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Dexamethasone belongs to the Corticosteroid class and Ketoconazole belongs to the Azole Antifungal class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Ketoconazole slows down how your body breaks down the steroid, which can cause the medicine to build up to high levels. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Dexamethasone has 21 total documented interactions on file in this dataset, and Ketoconazole has 113. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: Your doctor may need to lower your steroid dose or watch you closely for side effects while you are taking both medicines. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Dexamethasone or Ketoconazole based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.