is now known that some medications, when used chronically, can result in
undesirable side effects that were not necessarily obvious or present within
most initial clinical trials. A delayed adverse drug effect or
interaction could easily occur with vitamin B12 since the time necessary for
most patients to become deficient can be delayed one or more years due to high
storage levels in the body. The table below summarizes common medications
that have been associated with reducing the levels of vitamin B12 as well as
the proposed mechanism for this interaction.1-12 The order of
listed medications is alphabetical and not reflective of severity or level of
chronic use of any of these medications has the potential to cause
complications related to vitamin B12 deficiency, which includes impaired DNA
synthesis, impaired cell division, hematopoiesis, hyperhomocysteinemia, and
metabolism of odd-chain fatty acids that is necessary in preventing
demyelination of nerves. As discussed in other articles in the database, the use of antacids seem to only impair protein bound vitamin B12
ingested from animal derived dietary sources.
- National Institutes of Health. Office of Dietary Supplements.
Dietary Supplement Fact Sheet: Vitamin B12. Bethesda, Maryland.
- Stopa EG, O'Brien R, Katz M. Effect of colchicine on guinea pig
intrinsic factor-vitamin B12 receptor. Gastroenterology
- Palopoli JJ, Waxman J. Colchicine neuropathy or vitamin B12 deficiency neuropathy? N Eng J Med 1987;317:1290-1.
- Kittang E, Aadland E, Schjonsby H. Effect of omeprazole on the
secretion of intrinsic factor, gastric acid and pepsin in man. Gut
- Force RW, Nahata MC. Effect of histamine H2-receptor antagonists on vitamin B12 absorption. Ann Pharmacother 1992;26:1283-6.
- Ruscin JM, Page RL 2nd, Valuck RJ. Vitamin B(12)
deficiency associated with histamine (2)-receptor antagonists and a
proton-pump inhibitor. Ann Pharmacother 2002;36:812-6.
WA, Shaw S, Jayatilleke K et al. Increased intake of calcium reverses
the B12 malabsorption induced by metformin. Diabetes Care
- de Jager J, Kooy A, Lehert P et al. Long term treatment with
metformin in patients with type 2 diabetes and risk of vitamin B-12
deficiency: randomised placebo controlled trial. BMJ. 2010;340:c2181.
- Saltzman JR, Kemp JA, Golner BB et al. Effect of hypochlorhydria
due to omeprazole treatment or atrophic gastritis on protein-bound
vitamin B12 absorption. J Am Coll Nutr 1994;13:584-91.
- Schenk BE, Festen HP, Kuipers EJ et al. Effect of short- and
long-term treatment with omeprazole on the absorption and serum levels
of cobalamin. Aliment Pharmacol Ther 1996;10:541-5.
- Bradford GS, Taylor CT. Omeprazole and vitamin B12 deficiency. Ann Pharmacother 1999;33:641-3.
- Bellou A, Aimone-Gastin I, De Korwin JD et al. Cobalamin
deficiency with megaloblastic anaemia in one patient under long-term
omeprazole therapy. J Intern Med 1996;240:161-4.