Metformin: what to know
Metformin is often the first medicine prescribed for type 2 diabetes. It's well-studied and effective — here's how to take it well.
How to take it
- Usually taken with food to reduce stomach upset.
- Extended-release versions can ease side effects — ask if it's right for you.
- Take it consistently; don't double up on missed doses.
Common side effects
Stomach upset, nausea, and diarrhea are common early on and often fade. Starting low and going slow helps. Long-term use can lower vitamin B12 — your doctor may check it.
When extra care is needed
- Kidney function matters — metformin is cleared by the kidneys, so it's adjusted or paused if kidneys are impaired.
- Around imaging with contrast dye or major surgery, it may be paused temporarily.
- Serious illness with dehydration warrants a call to your provider.
Alcohol: Heavy drinking with metformin can raise a rare risk — ask your pharmacist what's safe for you.
Check your own medicines free
See how your prescriptions, supplements, and food may interact — organized by the part of the body they affect.
Open the medication tool →Important: This article is educational and not medical advice. It does not replace your pharmacist or prescriber. Always confirm decisions about your medicines with a qualified professional, and call your local emergency number for emergencies. In the U.S., Poison Control is 1-800-222-1222.