What the FDA labels say about taking them together
Ascorbic acid and erythromycin
Ascorbic acid's FDA label of May 29, 2026 names erythromycin in its drug interactions section; the erythromycin labels PlainMeds reads (4) do not name ascorbic acid. The ascorbic acid label: “DRUG INTERACTIONS Antibiotics: Ascorbic acid may decrease the activities of erythromycin, kanamycin, streptomycin, doxycycline, and lincomycin.”
Check it at the source: the ascorbic acid FDA label on DailyMed (effective May 29, 2026, McGuff Pharmaceuticals, Inc.); the erythromycin FDA label on DailyMed (effective August 1, 2024, Teva Pharmaceuticals USA, Inc.).
What does the ascorbic acid label say about erythromycin?
Ascorbic acid label, drug interactionsDRUG INTERACTIONS Antibiotics: Ascorbic acid may decrease the activities of erythromycin, kanamycin, streptomycin, doxycycline, and lincomycin.
Source: FDA drug label (Ascor), McGuff Pharmaceuticals, Inc., effective May 29, 2026 (SPL set 388aad52-fc01-4784-9791-1dbc80c69306), via openFDA; the full label on DailyMed
What does the erythromycin label say about ascorbic acid?
Erythromycin's label (effective August 1, 2024) and its 3 other brand-application labels do not name ascorbic acid 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
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
| Ascorbic acid | Erythromycin | |
|---|---|---|
| Labeled for | n/a | Bacterial infections, Acne |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | n/a | $1.96 per tablet 250 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