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Drug interactions

Erythromycin lactobionate + Itraconazole

Severity: Major

Erythromycin lactobionate and Itraconazole: major 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

Both drugs prolong the QT interval and are CYP3A4 substrates and inhibitors, so each may raise the level of the other. Intravenous erythromycin adds a high peak concentration, increasing the risk of torsades de pointes.

What this interaction means in plain words

Erythromycin lactobionate and Itraconazole 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; Itraconazole belongs to Anti Fungals.

Evidence level: Moderate

Why it happens

Additive QT prolongation with bidirectional CYP3A4 inhibition.

What to do

Avoid the combination and choose a non-macrolide antibiotic when possible. If needed, 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?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

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References

Frequently asked questions

Can I take Erythromycin lactobionate with Itraconazole?

MediHelp rates the interaction as major. Erythromycin lactobionate and Itraconazole 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 prolong the QT interval and are CYP3A4 substrates and inhibitors, so each may raise the level of the other. Intravenous erythromycin adds a high peak concentration, increasing the risk of torsades de pointes.

How serious is the interaction between Erythromycin lactobionate and Itraconazole?

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 and choose a non-macrolide antibiotic when possible. If needed, monitor ECG and correct potassium and magnesium.

What other medicines interact with Itraconazole?

MediHelp also lists interactions of Itraconazole with, for example, Alfuzosin, Alprazolam, Avanafil. The full list is on the Itraconazole page.

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