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Effect of Histamine H 2 -Receptor Antagonists on Vitamin B 12 Absorption

1992; SAGE Publishing; Volume: 26; Issue: 10 Linguagem: Inglês

10.1177/106002809202601018

1542-6270

Rex W. Force, Milap C. Nahata,

Vitamin D Research Studies

OBJECTIVE: To discuss the potential of histamine H 2 -receptor antagonists (H 2 RAs) to cause malabsorption of vitamin B 12 (cyanocobalamin). DATA SOURCES: Pertinent literature was identified via a MEDLINE search. Journals and references cited in published articles also were used as data sources. STUDY SELECTION: Studies evaluating the effect of H 2 RAs on vitamin B 12 absorption were reviewed. DATA SYNTHESIS: H 2 RAs decrease acid secretion by the gastric parietal cells. Gastric acid and pepsin produced by these cells are required for the cleavage of vitamin B 12 from dietary sources. Intrinsic factor (IF), also produced by gastric parietal cells, is required for vitamin B 12 absorption from the gastrointestinal tract. Although H 2 RAs have not conclusively been shown to decrease IF secretion, studies have demonstrated a significant reduction in food-bound vitamin B 12 absorption secondary to decreased acid secretion in patients taking these drugs. CONCLUSIONS: H 2 RAs have the potential to cause vitamin B 12 deficiency. This may be important in patients with inadequate stores of vitamin B 12 (e.g., poor diet), particularly those receiving H 2 RA therapy continuously for more than two years. Healthcare providers should be aware of this potential adverse effect.