Drug interactions
Erythromycin + Zafirlukast
Severity: Minor
Erythromycin and Zafirlukast: 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
Zafirlukast mainly inhibits CYP2C9 and has only weak CYP3A4 inhibition, so a meaningful rise in erythromycin levels is not well established. Another effect noted is that erythromycin may lower zafirlukast levels modestly. Clinical significance is likely small.
What this interaction means in plain words
Erythromycin and Zafirlukast 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 belongs to Anti Bacterial; Zafirlukast belongs to Respiratory.
Why it happens
Possible weak CYP3A4 effects; erythromycin has been reported to reduce zafirlukast bioavailability, but the mechanism is not firmly established.
What to do
No dose adjustment is routinely needed; monitor asthma control if coadministered.
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 Zafirlukast
- Pimozide + Zafirlukast Contraindicated
- Lomitapide + Zafirlukast Major
- Nilotinib + Zafirlukast Major
- Warfarin + Zafirlukast Major
- Apalutamide + Zafirlukast Moderate
- Carbamazepine + Zafirlukast Moderate
Frequently asked questions
Can I take Erythromycin with Zafirlukast?
MediHelp rates the interaction as minor. Erythromycin and Zafirlukast have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Zafirlukast mainly inhibits CYP2C9 and has only weak CYP3A4 inhibition, so a meaningful rise in erythromycin levels is not well established. Another effect noted is that erythromycin may lower zafirlukast levels modestly. Clinical significance is likely small.
How serious is the interaction between Erythromycin and Zafirlukast?
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 dose adjustment is routinely needed; monitor asthma control if coadministered.
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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