What the FDA labels say about taking them together
Erythromycin and zafirlukast
Zafirlukast's FDA label of December 1, 2023 names erythromycin in its drug interactions section; the erythromycin labels PlainMeds reads (4) do not name zafirlukast. The zafirlukast label: “In a drug interaction study in 11 asthmatic patients, coadministration of a single dose of zafirlukast (40 mg) with erythromycin to steady-state resulted in decreased mean plasma levels of zafirlukast by approximately …”
Check it at the source: the erythromycin FDA label on DailyMed (effective August 1, 2024, Teva Pharmaceuticals USA, Inc.); the zafirlukast FDA label on DailyMed (effective December 1, 2023, Aurobindo Pharma Limited).
What does the erythromycin label say about zafirlukast?
Erythromycin's label (effective August 1, 2024) and its 3 other brand-application labels do not name zafirlukast in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Erythromycin), Teva Pharmaceuticals USA, Inc., effective August 1, 2024 (SPL set 75a0bd5a-d09f-483b-bfd8-f8343b149eb2), via openFDA; the full label on DailyMed
What does the zafirlukast label say about erythromycin?
Zafirlukast label, drug interactionsIn a drug interaction study in 11 asthmatic patients, coadministration of a single dose of zafirlukast (40 mg) with erythromycin (500 mg three times daily for 5 days) to steady-state resulted in decreased mean plasma levels of zafirlukast by approximately 40% due to a decrease in zafirlukast bioavailability.
Source: FDA drug label (Zafirlukast), Aurobindo Pharma Limited, effective December 1, 2023 (SPL set 8bdb47c5-9d19-4d59-94c8-62c117525e7f), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Erythromycin | Zafirlukast | |
|---|---|---|
| Labeled for | Bacterial infections, Acne | Asthma |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $1.96 per tablet 250 mg tablet | $0.623 per tablet 20 mg tablet |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once