Vitamin B12 Deficiency in consumption of Metformin and Proton Pump Inhibitors

Abstract

The spectrum of diseases associated with vitamin B12 deficiency is broad, ranging from no symptoms to malabsorption syndrome, spinal cord injury, neurological symptoms accompanied by paresthesia, myelopathy, or neuropathy. There is suggestive evidence that long-term use of proton pump inhibitors (PPIs) can lower serum levels of vitamin B12. Additionally, previous studies have associated vitamin B12 deficiency with high doses consumption of metformin; however, the mechanism in which this occurs is not clear. An additive association between the administration of proton pump inhibitors / Histamine H2 receptor antagonists, and metformin has been described, which suggest that these promote vitamin B12 malabsorption. Both categories of drugs are widely used, in many cases without a prescription, and its use should not be overlooked. When clinically indicated, their use should be monitored in view of the possibility of vitamin B12 malabsorption and its consequences. This article aims to review general aspects of vitamin B12 and delve into the state of the art regarding vitamin B12 deficiency in patients with metformin and / or proton pump inhibitor consumption.