Drug interactions
Cilostazol + Ketoconazole
Severity: Major
Cilostazol and Ketoconazole: major interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Ketoconazole increases cilostazol exposure, which can heighten headache, tachycardia, palpitations and diarrhea, and potentially cardiovascular risk.
What this interaction means in plain words
Cilostazol and Ketoconazole can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Cilostazol belongs to Cardiovascular; Ketoconazole belongs to Anti Fungals.
Why it happens
Ketoconazole inhibits CYP3A4, reducing cilostazol clearance.
What to do
Reduce cilostazol to 50 mg twice daily during ketoconazole therapy and monitor for adverse effects. Avoid the combination in patients with heart failure.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
Other interactions of Cilostazol
Frequently asked questions
Can I take Cilostazol with Ketoconazole?
MediHelp rates the interaction as major. Cilostazol and Ketoconazole can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Ketoconazole increases cilostazol exposure, which can heighten headache, tachycardia, palpitations and diarrhea, and potentially cardiovascular risk.
How serious is the interaction between Cilostazol and Ketoconazole?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Reduce cilostazol to 50 mg twice daily during ketoconazole therapy and monitor for adverse effects. Avoid the combination in patients with heart failure.
What other medicines interact with Ketoconazole?
MediHelp also lists interactions of Ketoconazole with, for example, Alfuzosin, Alprazolam, Avanafil. The full list is on the Ketoconazole page.
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