Drug interactions
Erythromycin + Mizolastine
Severity: Contraindicated
Erythromycin and Mizolastine: contraindicated 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
Erythromycin raises mizolastine concentrations, and mizolastine can prolong the QT interval. The combination increases the risk of serious ventricular arrhythmias including torsades de pointes. Mizolastine labeling advises against use with macrolides.
What this interaction means in plain words
Erythromycin 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
Erythromycin inhibits CYP3A4 metabolism of mizolastine, with additive QT prolongation risk.
What to do
Do not coadminister; use a non-sedating antihistamine without QT effects such as cetirizine or a different antibiotic.
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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References
Other interactions of Erythromycin
- Conivaptan + Erythromycin Contraindicated
- Dihydroergotamine intranasal + Erythromycin Contraindicated
- Dihydroergotamine + Erythromycin Contraindicated
- Domperidone + Erythromycin Contraindicated
- Dronedarone + Erythromycin Contraindicated
- Droperidol + Erythromycin Contraindicated
Frequently asked questions
Can I take Erythromycin with Mizolastine?
MediHelp rates the interaction as contraindicated. Erythromycin 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. Erythromycin raises mizolastine concentrations, and mizolastine can prolong the QT interval. The combination increases the risk of serious ventricular arrhythmias including torsades de pointes. Mizolastine labeling advises against use with macrolides.
How serious is the interaction between Erythromycin 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: Do not coadminister; use a non-sedating antihistamine without QT effects such as cetirizine or a different antibiotic.
What other medicines interact with Erythromycin?
MediHelp also lists interactions of Erythromycin with, for example, Conivaptan, Dihydroergotamine intranasal, Dihydroergotamine. The full list is on the Erythromycin page.
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