What the FDA labels say about taking them together
Erythromycin and quinine
Quinine's FDA label of November 9, 2023 names erythromycin in its drug interactions (prescription label) section; the erythromycin labels PlainMeds reads (4) do not name quinine. The quinine label: “Macrolide Antibiotics (CYP3A4 Inhibitors) In a crossover study (N=10), healthy subjects who received a single oral 600 mg dose of quinine sulfate with the macrolide antibiotic, troleandomycin (500 mg every 8 hours) …”
Check it at the source: the erythromycin FDA label on DailyMed (effective August 1, 2024, Teva Pharmaceuticals USA, Inc.); the quinine FDA label on DailyMed (effective November 9, 2023).
What does the erythromycin label say about quinine?
Erythromycin's label (effective August 1, 2024) and its 3 other brand-application labels do not name quinine 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 quinine label say about erythromycin?
Quinine label, drug interactions (prescription label)Macrolide Antibiotics (Erythromycin, Troleandomycin) (CYP3A4 Inhibitors) In a crossover study (N=10), healthy subjects who received a single oral 600 mg dose of quinine sulfate with the macrolide antibiotic, troleandomycin (500 mg every 8 hours) exhibited a 87% higher mean quinine AUC, a 45% lower mean oral clearance of quinine, and a 81% lower formation clearance of the main metabolite, 3-hydroxy quinine, than when quinine was given alone.
Quinine label, warnings and precautions (prescription label)The use of macrolide antibiotics such as erythromycin should be avoided in patients receiving quinine sulfate.
Source: FDA drug label (Chininum sulphuricum), Boiron, effective November 9, 2023 (SPL set 33885950-2a55-11e7-8288-424c58303031), 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 | Quinine | |
|---|---|---|
| Labeled for | Bacterial infections, Acne | n/a |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $1.96 per tablet 250 mg tablet | $0.698 per capsule 324 mg capsule |
| 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