Metformin is the most widely prescribed first-line medication for type 2 diabetes globally. It has been in clinical use since the 1950s with an excellent long-term safety record.
How it works
Metformin reduces glucose production by the liver (hepatic gluconeogenesis) and improves insulin sensitivity in peripheral tissues. It does not cause hypoglycemia when used alone.
Common uses
First-line therapy for type 2 diabetes. Also used off-label for PCOS (to improve insulin resistance and ovulation) and prediabetes. Some evidence for longevity benefits continues to be investigated.
Side effects and precautions
GI side effects (nausea, diarrhea) are common in the first 2 weeks. Starting at low dose (500mg) and titrating up helps. Contraindicated in severe kidney disease (eGFR below 30).