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International Primary Care Association

Clinical Focus Volume 1 N3

Vitamin B12 Supplementation for Metformin-Induced Deficiency


Vitamin B12 deficiency is associated with metformin treatment, and can result in raised plasma homocysteine, a well established cardiovascular risk factor. The mechanism of vitamin B12 deficiency in these patients is not well defined, but has been linked to relative hypocalcaemia. The question of oral B12 replacement has been raised, and studies have shown that oral replacement with high doses (1000- 2000mcg/day) may be necessary for normalisation of B12 and homocysteine levels. While this has not been directly assessed for diabetics with metformin-induced B12 deficiency, we would recommend a trial of replacement with high dose oral cyanocobalamin, with calcium replacement if appropriate. Patients in whom this treatment strategy fails should be treated with standard intramuscular hydroxycobalamin replacement as for pernicious anaemia.

Additional Info

  • Authors: N Roy & F Shah
  • Keywords: Vitamin B12, metformin, homocysteine
  • Login: Please login to view Full Text of the article
Read 3918 times Last modified on Friday, 23 November 2012 16:15

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