Metformin-related vitamin B12 deficiency

Age Ageing. 2006 Mar;35(2):200-1. doi: 10.1093/ageing/afj042.


Metformin is an invaluable hypoglycaemic agent. We report two cases who had symptomatic vitamin B12 deficiency related to metformin use; the mechanisms are discussed. The clinician must be aware of the possibility of metformin-associated B12 deficiency in users who suffer cognitive impairment, peripheral neuropathy, subacute combined degeneration of the cord or anaemia.

Publication types

  • Case Reports

MeSH terms

  • Aged, 80 and over
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Diarrhea / chemically induced
  • Female
  • Humans
  • Hypoglycemic Agents / adverse effects*
  • Hypoglycemic Agents / therapeutic use
  • Metformin / adverse effects*
  • Metformin / therapeutic use
  • Vitamin B 12 Deficiency / chemically induced*


  • Hypoglycemic Agents
  • Metformin