Drug interactions
Erythromycin lactobionate + Tamoxifen
Severity: Minor
Erythromycin lactobionate and Tamoxifen: minor 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
Intravenous erythromycin inhibits CYP3A4 and may reduce formation of N-desmethyltamoxifen, altering tamoxifen exposure. The clinical effect is likely small and short-lived with a typical antibiotic course.
What this interaction means in plain words
Erythromycin lactobionate and Tamoxifen have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Erythromycin lactobionate belongs to Anti Bacterial; Tamoxifen belongs to Endocrine.
Why it happens
Erythromycin inhibits CYP3A4-mediated N-demethylation of tamoxifen.
What to do
No routine dose change is needed for a short course. If therapy is prolonged, consider a non-CYP3A4-inhibiting antibiotic.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Tamoxifen
- Amiodarone + Tamoxifen Major
- Anastrozole + Tamoxifen Major
- Bupropion + Tamoxifen Major
- Carbamazepine + Tamoxifen Major
- Cinacalcet + Tamoxifen Major
- Dacomitinib + Tamoxifen Major
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 Tamoxifen?
MediHelp rates the interaction as minor. Erythromycin lactobionate and Tamoxifen have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Intravenous erythromycin inhibits CYP3A4 and may reduce formation of N-desmethyltamoxifen, altering tamoxifen exposure. The clinical effect is likely small and short-lived with a typical antibiotic course.
How serious is the interaction between Erythromycin lactobionate and Tamoxifen?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No routine dose change is needed for a short course. If therapy is prolonged, consider a non-CYP3A4-inhibiting antibiotic.
What other medicines interact with Tamoxifen?
MediHelp also lists interactions of Tamoxifen with, for example, Amiodarone, Anastrozole, Bupropion. The full list is on the Tamoxifen page.
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