Drug interactions
Erythromycin + Guanfacine
Severity: Moderate
Erythromycin and Guanfacine: 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
Erythromycin raises guanfacine plasma concentrations through CYP3A4 inhibition. This can cause excessive hypotension, bradycardia and sedation.
What this interaction means in plain words
Erythromycin and Guanfacine 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; Guanfacine belongs to Cardiovascular.
Why it happens
Inhibition of CYP3A4-mediated guanfacine metabolism by erythromycin increases systemic exposure.
What to do
With extended-release guanfacine, halve the dose while erythromycin is given, and monitor blood pressure and heart rate. Raise the dose again after erythromycin is stopped.
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 Guanfacine
- Clonidine + Guanfacine Major
- Guanfacine + Lofexidine Major
- Aldesleukin + Guanfacine Moderate
- Amiodarone + Guanfacine Moderate
- Amisulpride + Guanfacine Moderate
- Amitriptyline + Guanfacine Moderate
Frequently asked questions
Can I take Erythromycin with Guanfacine?
MediHelp rates the interaction as moderate. Erythromycin and Guanfacine 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 raises guanfacine plasma concentrations through CYP3A4 inhibition. This can cause excessive hypotension, bradycardia and sedation.
How serious is the interaction between Erythromycin and Guanfacine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: With extended-release guanfacine, halve the dose while erythromycin is given, and monitor blood pressure and heart rate. Raise the dose again after erythromycin is stopped.
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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