Clarithromycin and Itraconazole Interaction
Drug interaction information between Clarithromycin and Itraconazole.
Clarithromycin and Itraconazole have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Clarithromycin and Itraconazole. 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
These two drugs interfere with each other's breakdown in the body, which can cause the levels of both to rise. This makes it more likely that you will experience side effects from either drug.
What To Do
Your doctor should watch you closely for any signs of side effects. They may need to adjust your treatment while you are taking both drugs.
FDA Label Information
Antifungals: Itraconazole Use With Caution Itraconazole: Both clarithromycin and itraconazole are substrates and inhibitors of CYP3A, potentially leading to a bi-directional drug interaction when administered concomitantly (see also Itraconazole under “Drugs That Affect Clarithromycin Tablets” in the table below). Clarithromycin may increase the plasma concentrations of itraconazole. Patients taking itraconazole and clarithromycin concomitantly should be monitored closely for signs or symptoms of increased or prolonged adverse reactions.
Clarithromycin Also Interacts With
- Quetiapine major
- Pioglitazone major
- Fluconazole major
- Cyclosporine major
- Lurasidone major
Itraconazole Also Interacts With
- Isavuconazonium major
- Lurasidone major
- Pimozide major
- Methadone major
- Midazolam major
Frequently Asked Questions
Can I take Clarithromycin and Itraconazole together?
This is a moderate interaction. Your doctor should watch you closely for any signs of side effects. They may need to adjust your treatment while you are taking both drugs.
How serious is the interaction between Clarithromycin and Itraconazole?
This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.
Why do Clarithromycin and Itraconazole interact?
These two drugs interfere with each other's breakdown in the body, which can cause the levels of both to rise. This makes it more likely that you will experience side effects from either drug.
Understanding the Clarithromycin and Itraconazole Interaction
FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Clarithromycin belongs to the Macrolide Antibiotic class and Itraconazole belongs to the Azole Antifungal class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: These two drugs interfere with each other's breakdown in the body, which can cause the levels of both to rise. 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. Clarithromycin has 81 total documented interactions on file in this dataset, and Itraconazole has 116. 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 should watch you closely for any signs of side effects. 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 Clarithromycin or Itraconazole 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.