Does Zonisamide Interact with Metformin?
The metformin label names zonisamide among carbonic anhydrase inhibitors. It connects their tendency to lower serum bicarbonate and cause metabolic acidosis with increased lactic-acidosis risk during metformin use.
Label evidence and limitations
Named-drug label evidence. The label recommends considering more frequent monitoring. This supports the warning but is not an FDA assignment of CDI’s major category or a patient-specific risk estimate.
Product scope: Oral metformin hydrochloride film-coated tablets.
Read the DailyMed label: These highlights do not include all the information needed to use METFORMIN HYDROCHLORIDE TABLETS safely and effectively. See full prescribing information for METFORMIN HYDROCHLORIDE TABLETS. METFORMIN HYDROCHLORIDE tablets, for oral use Initial U.S. Approval: 1995
Section: 7 Drug Interactions — Carbonic Anhydrase Inhibitors. Compared version 1, label date 2026-10-09. The linked label may be updated after this comparison.
The original record has no saved label identifier. This comparison uses a label located during the source check; it does not recover the original extraction source.
AI-assisted source comparison dated 2026-10-16. This is a comparison of label text, not independent clinical review or an individual safety assessment. CDI's stored severity category is not an FDA-assigned rating. Confirm your exact medicines and formulations with your pharmacist or prescriber before changing treatment.
- Stored CDI classification
- Major
- Zonisamide Class
- Anti-epileptic Agent
- Management
- Confirm exact products with your pharmacist
- Data Source
- Product label via NLM DailyMed
What To Tell Your Doctor or Pharmacist
If you are taking Zonisamide and your doctor is considering prescribing Metformin (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Never stop or change either medication without first consulting your healthcare provider