Alosetron and Ketoconazole Interaction
Drug interaction information between Alosetron and Ketoconazole.
Alosetron and Ketoconazole have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Alosetron 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 stops the body from breaking down alosetron as quickly as usual, which increases the amount of drug in your blood.
What To Do
Your doctor may need to watch you more closely for side effects while you are taking both drugs.
FDA Label Information
7.2 CYP3A4 Inhibitors Ketoconazole is a known strong inhibitor of CYP3A4. In a pharmacokinetic study, 38 healthy female subjects received ketoconazole 200 mg twice daily for 7 days, with coadministration of alosetron 1 mg on the last day. Ketoconazole increased mean alosetron plasma concentrations (AUC) by 29%.
Alosetron Also Interacts With
- Clarithromycin moderate
- Itraconazole moderate
- Voriconazole moderate
- Estradiol minor
- Hydralazine minor
Ketoconazole Also Interacts With
- Alfuzosin major
- Dronedarone major
- Ranolazine major
- Saxagliptin major
- Sildenafil major
Frequently Asked Questions
Can I take Alosetron and Ketoconazole together?
This is a minor interaction. Your doctor may need to watch you more closely for side effects while you are taking both drugs.
How serious is the interaction between Alosetron and Ketoconazole?
This interaction is classified as "minor" severity by the FDA. Minor interactions are unlikely to cause significant problems but should still be mentioned to your healthcare provider.
Why do Alosetron and Ketoconazole interact?
Ketoconazole stops the body from breaking down alosetron as quickly as usual, which increases the amount of drug in your blood.
Understanding the Alosetron and Ketoconazole Interaction
FDA-approved prescribing information for these two drugs flags their combination as a minor-severity interaction. Alosetron belongs to the 5-HT3 Antagonist (IBS-D) 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 stops the body from breaking down alosetron as quickly as usual, which increases the amount of drug in your blood. 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. Alosetron has 12 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 watch you more closely for side effects while you are taking both drugs. 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 Alosetron 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.