The People's Perspective on Medicine

Omeprazole and Metformin Combined to Cause Vitamin B12 Deficiency

A common drug combination, metformin for diabetes and an acid-suppressing drug for heartburn, can cause vitamin B12 deficiency.

Gastroenterologists have been very enthusiastic about proton pump inhibitors, PPIs. These acid-suppressing drugs work extremely well in treating ulcers and severe reflux disease. Physicians often prescribe them for a wide range of digestive difficulties, including heartburn or indigestion. But could such medications trigger vitamin B12 deficiency?

Tingling Feet and Bad Balance:

Q. My best friend has been having increasing difficulty this year with numbness and tingling in her feet and a loss of balance. Her doctor chalked it up to her age (79). When she fell in her bathroom and hit her head, she landed in the ICU where a neurologist diagnosed her with vitamin B12 deficiency.

She has been getting injections of vitamin B12, and although she can see some improvement, she still has poor balance. She had been taking omeprazole (Prilosec) for heartburn and metformin for type 2 diabetes. Apparently both drugs can trigger this deficiency. Why don’t doctors pay attention to the side effects of the drugs they prescribe?

A. Your friend is the victim of a double whammy. Vitamin B12 deficiency has long been recognized as a serious complication of the diabetes drug metformin (Internal and Emergency Medicine, Feb., 2015).

A recent study showed that acid suppressing drugs such as omeprazole, lansoprazole (Prevacid) or esomeprazole (Nexium) can also lead to vitamin B12 deficiency (JAMA, Dec. 11, 2013). We discussed this research with the lead investigator. Older people may be especially susceptible, since they frequently have less stomach acid and lower vitamin B12 stores.

Double Difficulty:

Taking both metformin and omeprazole or other PPI could definitely boost the possibility of developing a vitamin B12 deficiency (Diabetes Care, Dec., 2012). This combination is not uncommon; it may cause particular problems for older adults who have more difficulty absorbing vitamin B12 even without interference from medications (Geriatrics & Gerontology International, Aug., 2015). Despite this, elderly people on metformin may not be monitored as closely as they should be for a vitamin B12 deficiency (Aging Clinical and Experimental Research, Feb. 22, 2016).

Consequences of Vitamin B12 Deficiency:

Low levels of this vitamin may cause irreversible nerve damage. Symptoms include numbness, tingling or pain in toes, feet or fingers, trouble walking, memory problems and confusion, depression or burning tongue. Other symptoms can include loss of appetite, constipation and anemia. People with inadequate vitamin B12 may be at higher risk of cardiovascular disease (Kardiologia Polska, online July 8, 2016; Journal of Nutrition, Health & Aging, 2016). Those with diabetes appear to have more inflammation and less control of blood sugar when their vitamin B12 levels are low (Nutrients, Feb. 26, 2016).

People taking any acid-suppressing medications should have vitamin B12 levels tested at least once a year. Those on metformin should also undergo testing periodically. If a vitamin B12 deficiency develops, it should be treated with supplemental vitamin B12.


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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies. .
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I too had a deficiency of B12, but didn’t know it, until I started on Metmorfin. Not long after I started, I read in one of the health articles I receive that it causes a B12 deficiency.
For over a year now, while still on Metmorfin, I’ve put Sublingual B12 tablets under my tongue each day & all the deficiency symptoms now stay away.
I need 8 tablets a day to maintain having no deficiency symptoms – if I don’t have 8, I know the next day.
They’re very cheap, and they work. They also taste pretty good :)

These two drugs do not need to be taken together to cause B12 deficiency. Each, alone, can do it. It may just become worse faster with both.

AND, what is scary, most physicians will misdiagnose it as something else and order a drug that might make it even worse.

The book, Could It Be B12?, describes in great detail many facts about B12 depletion.


Is sublingual Vit. B12 on rx. or OTC ?


I have been taking omeprazole for many years and also Metformin for type 2 diabetes. I am 74 years old and suddenly had attack of “Drop Vertigo” in May and again in June with terrible symptoms of vomiting and severe sweating and totally incapacitated. now have been having tingling and terrible attacks like panicky and nervous jitters. ER doctor said vit B deficiency. Recommended my doctor check my vit B and give injections. Is vertigo from Vit b deficiency? please help.

For what I read, many people taking metformin have B12 deficiency. It’s not well absorbed.

@MLH I do not recommend Neurontin having taken it with no results except side effects. It does have some nasty side effects. What worked for me was sublingual Methylcobalamin vitamin B12 5000mcg and Alpha Lipoic Acid 1800 mg, in divided doses, 600 mg 3xday. I had no side effects. I had peripheral neuropathy from an undiagnosed B12 deficiency. I am not a medical practitioner.

I have tingling fingertips in 1 hand, apparently from severe cervical spine arthritis. Are there any home remedies?
I am to start Neurontin but would prefer no meds. I take only thyroid supplement, vitamin & mineral supplements, OTC probiotic & lactase with cheese, etc. I am allergic to penicillin & anti-inflammatories.

I have been using prescription antacid meds for years. I also have been diagnosed with neuropathy causing my feet to feel extremely cold but are warm to the touch and there is no circulatory issue. I haven’t checked my B-12 levels but intend to do so. Could the “cold feet” be a similar symptom caused by the same antacids?

I got the same symptoms and B12 deficiency after taking pantaprazole and metformin over time. I used the People’s Pharmacy recommendations on how to get off the GERD meds and it worked.
Biggest thing for me was to minimize the meal size at night. Now I’m off the GERD med, the peripheral neuropathy is gone. The B12 deficiency is gone. Still have depression, but there are multiple contributors for that and it’s slowly getting better. I received no warnings from my docs on the potential B12 problems and only found out during a yearly blood screening test result. Doc wanted me to take vitamin supplements, but to heck with taking more pills to cover up problems resulting from other pills.
Change as much of your lifestyle as you can to get off as much medication as you can. The stuff has been just terrible to me with all the side effects I’ve suffered. The docs don’t know it all and seem to rely on scripts for more pills rather than working to help you reduce your meds. Bless the People’s Pharmacy for giving me alternatives that have helped me get better.

Article would have been much more informative if it had included ranges of B12 for people to take. B12 dosages were provided only in a response.

My husband has severe neuropathy and has taken acid reducing medication for over twenty years. He has low B12. Two neurologists have told him he must take 1000 mg b12 daily. He takes sublingual B12, which is very inexpensive. B12 is necessary for all neurological functions and is obtained from food by the normal acid in the stomach. If acid is suppressed it can not release B12.
Sublingual B12 dissolves under tongue and goes directly into system.
I look forward to this newsletter each week.

There is more than one type of B12. My doctor prescribed B12 Methyl injections for symptoms of peripheral neuropathy. It worked! Well!
Another doctor switched me over to Cyno B12 injections (cheaper). My PN symptoms came back strongly. My understanding is that some people’s systems do not change the cyno to methyl in the body. As for myself, of course I have switched back to Methyl. All PN symptoms are gone.

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