Drug interactions
Fexofenadine + Ketoconazole
Severity: Minor
Fexofenadine 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 increases fexofenadine plasma concentrations, probably by inhibiting P-glycoprotein transport. Studies did not show meaningful changes in QT interval or safety.
What this interaction means in plain words
Fexofenadine 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.
Fexofenadine belongs to Respiratory; Ketoconazole belongs to Anti Fungals.
Why it happens
Inhibition of P-glycoprotein-mediated efflux of fexofenadine by ketoconazole.
What to do
No dose adjustment is generally required. Monitor for increased antihistamine adverse effects.
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 Fexofenadine
- Danicopan + Fexofenadine Moderate
- Erdafitinib + Fexofenadine Moderate
- Fexofenadine + Glecaprevir / pibrentasvir Moderate
- Fexofenadine + Grapefruit Moderate
- Fexofenadine + Juice Moderate
- Acrivastine + Fexofenadine 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 Fexofenadine with Ketoconazole?
MediHelp rates the interaction as minor. Fexofenadine 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 increases fexofenadine plasma concentrations, probably by inhibiting P-glycoprotein transport. Studies did not show meaningful changes in QT interval or safety.
How serious is the interaction between Fexofenadine 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 required. Monitor for increased antihistamine adverse effects.
What other medicines interact with Fexofenadine?
MediHelp also lists interactions of Fexofenadine with, for example, Danicopan, Erdafitinib, Glecaprevir / pibrentasvir. The full list is on the Fexofenadine page.
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