Gilteritinib and Clarithromycin: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Clarithromycin
Gilteritinib
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased gilteritinib plasma concentrations
Interaction Deep Dive
Concomitant use of gilteritinib (CYP3A substrate) with a strong CYP3A inhibitor increases gilteritinib exposure. In a drug interaction study, concomitant use of gilteritinib with itraconazole (a strong CYP3A inhibitor) increased gilteritinib exposure (Cmax by 20% and AUC by 120%). Consider alternative therapies that do not include a strong CYP3A inhibitor. If concomitant use is essential, monitor the patient more frequently for gilteritinib-associated adverse events and interrupt and reduce the gilteritinib dosage in patients with serious or life-threatening toxicity1.
Why it happens (mechanism)
Inhibition of CYP3A-mediated gilteritinib metabolism
Literature reports
1 report — tap to read
a) Concomitant use of gilteritinib with itraconazole (a strong CYP3A inhibitor) increased gilteritinib Cmax by approximately 20% and increased the AUC approximately 120% 1.
Common questions
Can I take Gilteritinib and Clarithromycin together?
Increased gilteritinib plasma concentrations Always confirm with your pharmacist or prescriber before making any change.
How serious is the Gilteritinib and Clarithromycin interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Gilteritinib or Clarithromycin need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (1)
- Product Information: XOSPATA(R) oral tablets, gilteritinib oral tablets. Astellas Pharma US Inc (per FDA), Northbrook, IL, 2022. DailyMed
Keep reading about Clarithromycin
Keep reading about Gilteritinib
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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