What the FDA labels say about taking them together
Acetazolamide and metformin
Metformin's FDA label of September 3, 2026 names acetazolamide in its drug interactions section; the acetazolamide label PlainMeds reads does not name metformin. The metformin label: “Carbonic anhydrase inhibitors frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. …”
Check it at the source: the acetazolamide FDA label on DailyMed (effective August 19, 2026, Strides Pharma Science Limited); the metformin FDA label on DailyMed (effective September 3, 2026, Granules India Ltd).
What does the acetazolamide label say about metformin?
Acetazolamide's label (effective August 19, 2026) does not name metformin in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Acetazolamide), Strides Pharma Science Limited, effective August 19, 2026 (SPL set 4813b9dd-5f58-44bb-ad64-cdb331828080), via openFDA; the full label on DailyMed
What does the metformin label say about acetazolamide?
Metformin label, drug interactionsCarbonic Anhydrase Inhibitors Clinical Impact: Carbonic anhydrase inhibitors frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of these drugs with metformin hydrochloride extended-release tablets may increase the risk for lactic acidosis. Intervention: Consider more frequent monitoring of these patients. Examples: Topiramate, zonisamide, acetazolamide or dichlorphenamide.
Source: FDA drug label (Riomet, NDA021591), Sun Pharmaceutical Industries, Inc., effective December 6, 2018 (SPL set 05d4df4b-dfe8-4828-b423-a3d4f2c4114a), via openFDA
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
| Acetazolamide | Metformin | |
|---|---|---|
| Labeled for | n/a | Type 2 diabetes |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.134 per tablet 250 mg tablet | $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