Drug-Induced Vitamin B12 Deficiency: A Focus on Proton Pump Inhibitors and Histamine-2 Antagonists

Abstract

Objective: To review primary literature of gastric acid suppressive agents and vitamin B12 deficiency. Data Synthesis: From the published articles, proton pump inhibitors (PPIs) are associated with a higher risk of inducing vitamin B12 deficiency than histamine-2 receptor antagonists (H2RAs). Literature suggests that there is an increased risk of developing vitamin B12 deficiency in patients who are exposed to extended durations of therapy with PPIs. There are, however, some conflicting data in elderly patients suggesting that the PPI use for more than 3 years does not increase the risk of vitamin B12 deficiency. No evidence was found to support the extended use of H2RA monotherapy causing vitamin B12 deficiency. The inconsistency of results reported could be due to the differing patient populations studied, such as Zollinger-Ellison syndrome (ZES) and elderly patients. Overall, the lack of consistent evidence shows the need for more research in this area. Conclusion: To investigate the clinical significance of vitamin B12 deficiency caused by acid suppression with PPIs and H2RAs, longer prospective studies are needed. These studies should focus on patient-centered outcomes to accurately determine the extended usage of PPI and H2RA and the true effects on vitamin B12 deficiency.