Drug interactions
Ketoconazole + Mizolastine
Severity: Contraindicated
Ketoconazole and Mizolastine: contraindicated 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 mizolastine levels, which may prolong the QT interval and lead to ventricular arrhythmias. Labeling contraindicates mizolastine with azole antifungals.
What this interaction means in plain words
Ketoconazole and Mizolastine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Why it happens
CYP3A4 inhibition by ketoconazole reduces mizolastine metabolism, adding to QT effects.
What to do
Avoid. Use a non-sedating antihistamine with lower QT risk and no CYP3A4 dependence, such as fexofenadine.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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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
Frequently asked questions
Can I take Ketoconazole with Mizolastine?
MediHelp rates the interaction as contraindicated. Ketoconazole and Mizolastine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Ketoconazole increases mizolastine levels, which may prolong the QT interval and lead to ventricular arrhythmias. Labeling contraindicates mizolastine with azole antifungals.
How serious is the interaction between Ketoconazole and Mizolastine?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid. Use a non-sedating antihistamine with lower QT risk and no CYP3A4 dependence, such as fexofenadine.
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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