Drug interactions
Ampicillin + Erythromycin
Severity: Minor
Ampicillin and Erythromycin: 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
A bacteriostatic macrolide may theoretically reduce the bactericidal action of ampicillin, but clinical evidence of reduced effectiveness is inconsistent. The combination is used in practice, for example in some obstetric and respiratory infections.
What this interaction means in plain words
Ampicillin and Erythromycin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Ampicillin belongs to Anti Bacterial; Erythromycin belongs to Anti Bacterial.
Why it happens
Theoretical pharmacodynamic antagonism between a bacteriostatic macrolide and a bactericidal beta-lactam.
What to do
No routine change is needed; monitor clinical response in serious infections such as meningitis or endocarditis.
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 Erythromycin
- Conivaptan + Erythromycin Contraindicated
- Dihydroergotamine intranasal + Erythromycin Contraindicated
- Dihydroergotamine + Erythromycin Contraindicated
- Domperidone + Erythromycin Contraindicated
- Dronedarone + Erythromycin Contraindicated
- Droperidol + Erythromycin Contraindicated
Other interactions of Ampicillin
- Allopurinol + Ampicillin Moderate
- Ampicillin + Bcg vaccine live Moderate
- Ampicillin + Chloramphenicol Moderate
- Ampicillin + Chloroquine Moderate
- Ampicillin + Cholera vaccine Moderate
- Ampicillin + Demeclocycline Moderate
Frequently asked questions
Can I take Ampicillin with Erythromycin?
MediHelp rates the interaction as minor. Ampicillin and Erythromycin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. A bacteriostatic macrolide may theoretically reduce the bactericidal action of ampicillin, but clinical evidence of reduced effectiveness is inconsistent. The combination is used in practice, for example in some obstetric and respiratory infections.
How serious is the interaction between Ampicillin and Erythromycin?
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 change is needed; monitor clinical response in serious infections such as meningitis or endocarditis.
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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