Drug interactions
Erythromycin lactobionate + Hydroxyzine
Severity: Major
Erythromycin lactobionate and Hydroxyzine: major interaction.
Last updated Sources: UK SmPC
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
Both drugs can prolong the QT interval, and intravenous erythromycin gives high peak levels, so combined use raises the risk of torsades de pointes. Erythromycin may also inhibit CYP3A4 and increase hydroxyzine exposure.
What this interaction means in plain words
Erythromycin lactobionate and Hydroxyzine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Erythromycin lactobionate belongs to Anti Bacterial; Hydroxyzine belongs to Respiratory.
Why it happens
Additive QT prolongation via cardiac potassium channel blockade, with possible CYP3A4 inhibition by erythromycin raising hydroxyzine levels.
What to do
Avoid the combination where possible and choose a non-QT-prolonging antibiotic or antihistamine. If unavoidable, monitor ECG and correct potassium and magnesium.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
- Hydroxyzine 10 mg film-coated tablets - SmPC sections 4.3/4.5 (names the partner; "some antibiotics (e.g. erythromycin, levofloxacin, moxifloxacin)") — electronic medicines compendium (UK SmPC)
Other interactions of Hydroxyzine
- Droperidol + Hydroxyzine Contraindicated
- Hydroxyzine + Pimozide Contraindicated
- Hydroxyzine + Thioridazine Contraindicated
- Hydroxyzine + Vandetanib Contraindicated
- Alfentanil + Hydroxyzine Major
- Amiodarone + Hydroxyzine Major
Other interactions of Erythromycin lactobionate
- Cisapride + Erythromycin lactobionate Contraindicated
- Dihydroergotamine + Erythromycin lactobionate Contraindicated
- Dronedarone + Erythromycin lactobionate Contraindicated
- Eletriptan + Erythromycin lactobionate Contraindicated
- Ergotamine + Erythromycin lactobionate Contraindicated
- Erythromycin lactobionate + Flibanserin Contraindicated
Frequently asked questions
Can I take Erythromycin lactobionate with Hydroxyzine?
MediHelp rates the interaction as major. Erythromycin lactobionate and Hydroxyzine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both drugs can prolong the QT interval, and intravenous erythromycin gives high peak levels, so combined use raises the risk of torsades de pointes. Erythromycin may also inhibit CYP3A4 and increase hydroxyzine exposure.
How serious is the interaction between Erythromycin lactobionate and Hydroxyzine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible and choose a non-QT-prolonging antibiotic or antihistamine. If unavoidable, monitor ECG and correct potassium and magnesium.
What other medicines interact with Hydroxyzine?
MediHelp also lists interactions of Hydroxyzine with, for example, Droperidol, Pimozide, Thioridazine. The full list is on the Hydroxyzine page.
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