Drug interactions
Erythromycin ethylsuccinate + Mirtazapine
Severity: Major
Erythromycin ethylsuccinate 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, so combined use raises the risk of torsades de pointes, especially with other risk factors. Erythromycin also inhibits CYP3A4 and may modestly raise mirtazapine exposure.
What this interaction means in plain words
Erythromycin ethylsuccinate 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.
Why it happens
Additive QT prolongation, plus CYP3A4 inhibition by erythromycin reducing mirtazapine clearance.
What to do
Prefer a non-macrolide antibiotic when feasible. If combined, obtain a baseline ECG, correct potassium and magnesium, and monitor QTc and for symptoms of arrhythmia.
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
Frequently asked questions
Can I take Erythromycin ethylsuccinate with Mirtazapine?
MediHelp rates the interaction as major. Erythromycin ethylsuccinate 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, so combined use raises the risk of torsades de pointes, especially with other risk factors. Erythromycin also inhibits CYP3A4 and may modestly raise mirtazapine exposure.
How serious is the interaction between Erythromycin ethylsuccinate 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: Prefer a non-macrolide antibiotic when feasible. If combined, obtain a baseline ECG, correct potassium and magnesium, and monitor QTc and for symptoms of arrhythmia.
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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