Does Fulvestrant Interact with Ketoconazole?
Fulvestrant and Ketoconazole have a unknown drug interaction according to U.S. FDA drug labeling data. Although, fulvestrant is metabolized by CYP 3A4 in vitro , drug interactions studies with ketoconazole or rifampin did not alter fulvestrant pharmacokinetics. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.
- Severity
- Unknown
- Fulvestrant Class
- Estrogen Receptor Antagonist
- Ketoconazole Class
- Azole Antifungal
- Management
- Consult your pharmacist
- Data Source
- U.S. FDA via OpenFDA
What To Tell Your Doctor or Pharmacist
If you are taking Fulvestrant and your doctor is considering prescribing Ketoconazole (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Never stop or change either medication without first consulting your healthcare provider