What the FDA labels say about taking them together
Cephalexin and metformin
Cephalexin's FDA label of December 31, 2020 names metformin in its drug interactions section; the metformin labels PlainMeds reads (3) do not name cephalexin. The cephalexin label: “DRUG INTERACTIONS Metformin: increased metformin concentrations.”
Check it at the source: the cephalexin FDA label on DailyMed (effective December 31, 2020, Teva Pharmaceuticals USA, Inc.); the metformin FDA label on DailyMed (effective September 3, 2026, Granules India Ltd).
What does the cephalexin label say about metformin?
Cephalexin label, drug interactionsDRUG INTERACTIONS Metformin: increased metformin concentrations.
Source: FDA drug label (Cephalexin), Teva Pharmaceuticals USA, Inc., effective December 31, 2020 (SPL set 19307ff0-71de-477b-965d-ea243e5ede3a), via openFDA; the full label on DailyMed
What does the metformin label say about cephalexin?
Metformin's label (effective September 3, 2026) and its 2 other brand-application labels do not name cephalexin in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (METFORMIN HYDROCHLORIDE), Granules India Ltd, effective September 3, 2026 (SPL set 73197cb5-3e23-4ac0-b189-f9bc848bce66), 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
| Cephalexin | Metformin | |
|---|---|---|
| Labeled for | Bacterial infections, Urinary tract infections | Type 2 diabetes |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.120 per capsule 500 mg capsule | $0.0145 per tablet 500 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