Drug interactions
Ketoconazole + Losartan
Severity: Minor
Ketoconazole and Losartan: 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 can inhibit conversion of losartan to its more potent active metabolite E-3174, potentially lessening the antihypertensive effect. The clinical importance appears limited and variable between patients.
What this interaction means in plain words
Ketoconazole and Losartan 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 belongs to Anti Fungals; Losartan belongs to Cardiovascular.
Why it happens
Ketoconazole inhibits CYP2C9 and CYP3A4, which convert losartan to E-3174.
What to do
Monitor blood pressure after starting or stopping ketoconazole and adjust the losartan dose if control changes.
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 Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
Other interactions of Losartan
- Aliskiren + Losartan Contraindicated
- Losartan + Sparsentan Contraindicated
- Amifostine + Losartan Major
- Amiloride + Losartan Major
- Amlodipine-benazepril + Losartan Major
- Amlodipine-hydrochlorothiazide-valsartan + Losartan Major
Frequently asked questions
Can I take Ketoconazole with Losartan?
MediHelp rates the interaction as minor. Ketoconazole and Losartan 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 can inhibit conversion of losartan to its more potent active metabolite E-3174, potentially lessening the antihypertensive effect. The clinical importance appears limited and variable between patients.
How serious is the interaction between Ketoconazole and Losartan?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood pressure after starting or stopping ketoconazole and adjust the losartan dose if control changes.
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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