Health Library · Medications

Metformin side effects

Overview

Metformin is first-line for type 2 diabetes and has a long safety record. GI side effects are common but often improve with time or extended-release formulation.

Symptoms to watch for

  • Nausea
  • Diarrhea
  • Metallic taste
  • Reduced appetite
  • Long-term: B12 deficiency

Treatment

Start low (500 mg with dinner), titrate slowly. Extended-release reduces GI side effects. Check B12 annually.