Abstract
To discuss the potential of histamine H2-receptor antagonists (H2RAs) to cause malabsorption of vitamin B12 (cyanocobalamin). Pertinent literature was identified via a MEDLINE search. Journals and references cited in published articles also were used as data sources. Studies evaluating the effect of H2RAs on vitamin B12 absorption were reviewed. H2RAs decrease acid secretion by the gastric parietal cells. Gastric acid and pepsin produced by these cells are required for the cleavage of vitamin B12 from dietary sources. Intrinsic factor (IF), also produced by gastric parietal cells, is required for vitamin B12 absorption from the gastrointestinal tract. Although H2RAs have not conclusively been shown to decrease IF secretion, studies have demonstrated a significant reduction in food-bound vitamin B12 absorption secondary to decreased acid secretion in patients taking these drugs. H2RAs have the potential to cause vitamin B12 deficiency. This may be important in patients with inadequate stores of vitamin B12 (e.g., poor diet), particularly those receiving H2RA therapy continuously for more than two years. Healthcare providers should be aware of this potential adverse effect.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
