Drug interactions
Amitriptyline + Erythromycin base
Severity: Major
Amitriptyline and Erythromycin base: major interaction.
Last updated
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 can raise amitriptyline concentrations and both drugs prolong the QT interval. This increases the risk of anticholinergic toxicity and ventricular arrhythmia.
What this interaction means in plain words
Amitriptyline and Erythromycin base 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
CYP3A4 inhibition by erythromycin reduces amitriptyline clearance, with additive QT prolongation.
What to do
Use an alternative antibiotic such as azithromycin with less interaction, or monitor ECG and tricyclic toxicity. Reduce the amitriptyline dose if needed.
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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Other interactions of Amitriptyline
- Amitriptyline + Isocarboxazid Contraindicated
- Amitriptyline + Methylene blue Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amitriptyline + Procarbazine Contraindicated
- Amitriptyline + Safinamide Contraindicated
Frequently asked questions
Can I take Amitriptyline with Erythromycin base?
MediHelp rates the interaction as major. Amitriptyline and Erythromycin base 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 can raise amitriptyline concentrations and both drugs prolong the QT interval. This increases the risk of anticholinergic toxicity and ventricular arrhythmia.
How serious is the interaction between Amitriptyline and Erythromycin base?
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 an alternative antibiotic such as azithromycin with less interaction, or monitor ECG and tricyclic toxicity. Reduce the amitriptyline dose if needed.
What other medicines interact with Amitriptyline?
MediHelp also lists interactions of Amitriptyline with, for example, Isocarboxazid, Methylene blue, Phenelzine. The full list is on the Amitriptyline page.
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