Drug interactions
Finasteride + Ketoconazole
Severity: Minor
Finasteride and Ketoconazole: minor interaction.
Last updated
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 strongly inhibits CYP3A4 and may raise finasteride levels. The clinical impact is usually small given finasteride's tolerability at higher exposures.
What this interaction means in plain words
Finasteride and Ketoconazole have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Finasteride belongs to Genitourinary; Ketoconazole belongs to Anti Fungals.
Why it happens
Ketoconazole inhibits CYP3A4-mediated finasteride metabolism.
What to do
No dose adjustment is generally needed. Monitor for finasteride adverse effects if ketoconazole is used long term.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Finasteride
- Finasteride + Levoketoconazole Moderate
- Finasteride + Nefazodone Moderate
- Finasteride + Rifampin Moderate
- Finasteride + St john's wort Moderate
- Amobarbital + Finasteride Minor
- Aprepitant + Finasteride Minor
Other interactions of Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
Frequently asked questions
Can I take Finasteride with Ketoconazole?
MediHelp rates the interaction as minor. Finasteride and Ketoconazole have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Ketoconazole strongly inhibits CYP3A4 and may raise finasteride levels. The clinical impact is usually small given finasteride's tolerability at higher exposures.
How serious is the interaction between Finasteride and Ketoconazole?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No dose adjustment is generally needed. Monitor for finasteride adverse effects if ketoconazole is used long term.
What other medicines interact with Finasteride?
MediHelp also lists interactions of Finasteride with, for example, Levoketoconazole, Nefazodone, Rifampin. The full list is on the Finasteride page.
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