Drug interactions
Erythromycin lactobionate + Mirtazapine
Severity: Major
Erythromycin lactobionate and Mirtazapine: major interaction.
Last updated Sources: Health Canada product monograph
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 concentrations that heighten the risk of torsades de pointes. Erythromycin also inhibits CYP3A4 and may raise mirtazapine exposure.
What this interaction means in plain words
Erythromycin lactobionate and Mirtazapine 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; Mirtazapine belongs to Central Nervous System.
Why it happens
Additive QT prolongation, plus CYP3A4 inhibition by erythromycin reducing mirtazapine clearance.
What to do
Use a non-macrolide alternative when possible. If combined, check ECG and electrolytes, keep potassium and magnesium normal, and monitor QTc during infusion.
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
Other interactions of Mirtazapine
- Isocarboxazid + Mirtazapine Contraindicated
- Mirtazapine + Phenelzine Contraindicated
- Mirtazapine + Pimozide Contraindicated
- Mirtazapine + Procarbazine Contraindicated
- Mirtazapine + Rasagiline Contraindicated
- Mirtazapine + Selegiline Contraindicated
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 Mirtazapine?
MediHelp rates the interaction as major. Erythromycin lactobionate and Mirtazapine 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 concentrations that heighten the risk of torsades de pointes. Erythromycin also inhibits CYP3A4 and may raise mirtazapine exposure.
How serious is the interaction between Erythromycin lactobionate and Mirtazapine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use a non-macrolide alternative when possible. If combined, check ECG and electrolytes, keep potassium and magnesium normal, and monitor QTc during infusion.
What other medicines interact with Mirtazapine?
MediHelp also lists interactions of Mirtazapine with, for example, Isocarboxazid, Phenelzine, Pimozide. The full list is on the Mirtazapine page.
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