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Prescribed Medicines Led to Vitamin B12 Deficiency

A PPI for GERD and metformin for type 2 diabetes combined to cause vitamin B12 deficiency for this reader; what is the appropriate treatment?

Medications can occasionally cause important nutritional deficiencies. That is especially true for drugs that are taken day after day for months or years. Certain widely-used medicines, especially those for acid reflux and one for diabetes, may fall into this category. One reader relates a frightening experience:

Q. I developed numbness and tingling in my feet due to vitamin B12 deficiency after taking pantoprazole and metformin for several years. I had received no warnings from my doctors about potential vitamin B12 deficiency and only found out during a yearly blood-screening test.

My doctor wanted me to take vitamins, but to heck with taking pills to cover up problems from other pills. I was able to get off pantoprazole, with some serious effort. What can I do for my diabetes?

Overcoming Vitamin B12 Deficiency Caused by Metformin:

A. Metformin is prescribed for diabetes, while pantoprazole (Protonix) is a proton pump inhibitor (PPI) used to suppress stomach acid production and treat severe heartburn or GERD (gastroesophageal reflux disease).

Consequences of Vitamin B12 Deficiency:

Both metformin and PPIs reduce the absorption of vitamin B12 from the stomach, which is why people must be tested for deficiency. Lack of vitamin B12 can lead to depression, irritability, confusion, poor muscle control and nerve damage that produces symptoms of numbness and tingling like yours. Constipation, loss of appetite and anemia are other possible symptoms. Lasting neurological damage is rare but may happen if the deficiency is not addressed.

The combination of a PPI with metformin may increase the possibility of this complication. We have heard of it happening before, as we wrote here.

The Usual Treatment Is Vitamin Supplements:

Generally, the treatment for vitamin B12 deficiency is supplemental vitamin B12 to replace the lost stores of this critical nutrient. This used to be delivered as a monthly cyanocobalamin injection. Research has shown, however, that taking a high-dose vitamin B12 orally (such as a 1 mg tablet) can also counteract poor absorption (Clinical Medicine, April, 2015).

Metformin may be the best treatment for your type 2 diabetes. There are, however, some other approaches that may allow you to reduce your dose of medication by concentrating on diet, exercise and stress relief along with certain botanical extracts. You can learn more about metformin as well as such nondrug approaches to controlling blood sugar in our Guide to Managing Diabetes.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.”.
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