Metformin is the most commonly prescribed diabetes medicine in the world, with more than 61 million prescriptions filled in the United States alone in 2012. Now, a new report from West Liberty University indicates that using this drug along with certain classes of medicine for gastroesophageal reflux disease (GERD) can lead to vitamin B12 deficiency and subsequent neuropathy, or nerve damage (an often painful condition that affects up to 70% of people with diabetes).
More than 40% of the 29 million people in the United States with diabetes also have GERD, and 70% of that population uses oral diabetes medicines such as metformin, making it likely that millions of people are using both GERD and diabetes drugs simultaneously. Both metformin and acid-suppressing GERD medicines from classes known as histamine H2-receptor antagonists (H2RAs) and proton pump inhibitors (PPIs) have the potential to cause vitamin B12 deficiency, which can lead to the development of neuropathy.
In reviewing studies on metformin, H2RAs, PPIs, and vitamin B12 deficiency, researcher Matthew J. Zdilla, DC, found that using both metformin and one of the GERD medicines was likely to further increase a person’s chances of developing vitamin B12 deficiency and resulting neuropathy beyond the risk of using just one of these medicines.
“Pharmacists, clinicians, and patients need to be aware of the potential for…B12 depletion [caused by the simultaneous use of multiple medicines] and the potential for subsequent neuropathy,” notes Zdilla. “Awareness is particularly important because metformin and acid-suppressing medications are commonly used in the diabetic population, which has a high prevalence of neuropathy.”
Zdilla referenced a variety of studies in which vitamin B12 either taken by mouth or through an injection was found to improve the symptoms of neuropathy in people with diabetes, suggesting that their conditions were due, at least in part, to B12 deficiency neuropathy rather than diabetic neuropathy.
For more information, see the article, “Metformin Plus GERD Medications Diminish Vitamin B12,” or see the report in the journal Clinical Diabetes. And for more information on the association between metformin and vitamin B12, click here.
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