Drug interactions
Amitriptyline + Erythromycin
Severity: Major
Amitriptyline and Erythromycin: 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 increase amitriptyline concentrations, and both drugs prolong the QT interval. This raises the risk of arrhythmia as well as anticholinergic and sedative effects.
What this interaction means in plain words
Amitriptyline and Erythromycin 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.
Amitriptyline belongs to Central Nervous System; Erythromycin belongs to Anti Bacterial.
Why it happens
CYP3A4 inhibition by erythromycin raising amitriptyline levels, plus additive QT prolongation.
What to do
Prefer a different antibiotic; if combined, obtain an ECG, correct electrolytes and monitor for tricyclic toxicity.
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 Erythromycin
- Conivaptan + Erythromycin Contraindicated
- Dihydroergotamine intranasal + Erythromycin Contraindicated
- Dihydroergotamine + Erythromycin Contraindicated
- Domperidone + Erythromycin Contraindicated
- Dronedarone + Erythromycin Contraindicated
- Droperidol + Erythromycin Contraindicated
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?
MediHelp rates the interaction as major. Amitriptyline and Erythromycin 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 increase amitriptyline concentrations, and both drugs prolong the QT interval. This raises the risk of arrhythmia as well as anticholinergic and sedative effects.
How serious is the interaction between Amitriptyline and Erythromycin?
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 different antibiotic; if combined, obtain an ECG, correct electrolytes and monitor for tricyclic toxicity.
What other medicines interact with Erythromycin?
MediHelp also lists interactions of Erythromycin with, for example, Conivaptan, Dihydroergotamine intranasal, Dihydroergotamine. The full list is on the Erythromycin page.
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