Drug interactions
Erythromycin + Valproic acid
Severity: Moderate
Erythromycin and Valproic acid: moderate 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
Case reports describe raised valproate concentrations and toxicity, including drowsiness, confusion and elevated ammonia, after erythromycin was started. The effect appears to be inconsistent but can be significant in individual patients.
What this interaction means in plain words
Erythromycin and Valproic acid can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Erythromycin belongs to Anti Bacterial; Valproic acid belongs to Central Nervous System.
Why it happens
Erythromycin may inhibit valproate metabolism, but the exact pathway is not firmly established.
What to do
Monitor for valproate toxicity and check serum valproate levels if erythromycin is added; reduce the valproate dose if levels are high, or choose a non-macrolide antibiotic.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Valproic acid
- Ertapenem + Valproic acid Contraindicated
- Imipenem / cilastatin / relebactam + Valproic acid Contraindicated
- Imipenem / cilastatin + Valproic acid Contraindicated
- Meropenem / vaborbactam + Valproic acid Contraindicated
- Meropenem + Valproic acid Contraindicated
- Calcium / magnesium / potassium / sodium oxybates + Valproic acid Major
Frequently asked questions
Can I take Erythromycin with Valproic acid?
MediHelp rates the interaction as moderate. Erythromycin and Valproic acid can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Case reports describe raised valproate concentrations and toxicity, including drowsiness, confusion and elevated ammonia, after erythromycin was started. The effect appears to be inconsistent but can be significant in individual patients.
How serious is the interaction between Erythromycin and Valproic acid?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for valproate toxicity and check serum valproate levels if erythromycin is added; reduce the valproate dose if levels are high, or choose a non-macrolide antibiotic.
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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