A little over 10 years ago I was diagnosed as having Diabetes Type 2, and I have been taking 500 MG of Metformin HCL twice daily ever since then. In 2007 I began experiencing Peripheral Neuropathy, or what appears to be popularly referred to today as Diabetic Nerve Pain. Sharp, almost excruciating, pain – a feeling like someone was sticking hot needles into my feet or toes – would frequently wake me up in the middle of the night. At other times I would feel a tingling sensation in my fingers; almost as if they had gone to sleep.
Being a proficient and knowledgeable computer user, I decided to research these problems on the Internet to see if I could determine a cause and find a solution for them before running off to my PCP. It only took a little while for me to discover an article posted by the Mayo Clinic that indicated the cause of my discomfort might be the result of long-term usage of the drug Metformin. While I am no longer able find that specific article, there is still enough information online to verify those findings. For example: ” Metformin, a common diabetes drug that helps control blood sugar levels, also may cause vitamin B-12 deficiency. But the relationship between diabetic neuropathy and metformin-induced vitamin B-12 deficiency isn’t well-understood.” (http://www.mayoclinic.org/diseases-conditions/diabetic-neuropathy/in-depth/diabetic-neuropathy-and-dietary-supplements/art-20095406).
“Metformin has been associated with vitamin B12 deficiency, and this is more likely to occur after more than 3 years of use. It is a dose-related phenomenon and more prevalent at dosages of more than 1.5 g/d.9 In a recent randomized trial using 2.5 g/d of metformin for 4 years, the treatment group had a 7.2% greater absolute risk of developing vitamin B12 deficiency (<200 pg/mL; to convert to pmol/L, multiply by 0.7378) vs the group receiving placebo.10 Homocysteine is often modestly elevated as well; however, in this case, checking for elevated homocysteine levels would not be indicated. The clinical severity is mild to moderate in most cases, with mild peripheral neuropathy and anemia (hemoglobin values in the 11 g/dL range) being the most common findings in symptomatic patients.
The mechanism is thought to be malabsorption of food cobalamin in the distal ileum. The ileal cell surface receptor depends on intraluminal calcium to function effectively, and metformin interferes with this interaction. In fact, one report of patients taking metformin indicated significant improvement in vitamin B12absorption with increased intake of calcium.” (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3012636/).
“One potential health problem from vitamin B12 deficiency is neuropathy, and almost 30% of diabetic patients older than 40 have impaired sensation in the feet.13 Unfortunately, the symptoms of diabetic neuropathy overlap with the paresthesias, impaired vibration sense, and impaired proprioception associated with B12 deficiency.14 As a result, B12 deficiency–induced nerve damage may be confused with or contribute to diabetic peripheral neuropathy.15 Identifying the correct etiology of neuropathy is crucial because simple vitamin B12 replacement may reverse neurologic symptoms inappropriately attributed to hyperglycemia” (http://www.jabfm.org/content/22/5/528.full).
Although the information quoted above has been taken from recent publications, similar information was noted in that Mayo posting that I originally discovered in 2007. Since my PCP had already scheduled me to have some lab work performed as a regular follow-up on my health in the near future, I called him and asked if he would consider adding a test to determine if I might have a Vitamin B-12 deficiency (specifically, a Methylcobalamin deficiency; There are other forms of B-12, but a “cobalamin” deficienty is apparently the one that causes the peripheral nueropathy), and he agreed. A visit to the lab a week later confirmed that I was indeed suffering from a Vitamin B-12 Methylcobalamin deficiency, and I started taking his recommended dosage of 1000 mcg’s daily. The stinging sensations that occurred in my feet and toes, and the numbing sensations in my fingers, soon began to lessen, and after a few weeks they rarely occurred. I have been taking 1000 mcg’s of Methylcobalamin for about 8 years now, and I rarely ever experience signs of Diabetic Nerve Pain or Peripheral Neuropathy these days (usually only if I forget to take my B-12). It is a pleasant tasting, quick dissolving, little pink pill that you place under your tongue. I started taking it at night, but I concluded that it might be contributing to my difficulty in falling asleep, so I began taking it after lunch and I still do so today).
PLEASE UNDERSTAND that I am NOT a doctor and I have absolutely no medical training; nor am I benefiting in any way from publishing this information. I am publishing this article because I believe too many people are being misinformed by the pill-pushing drug companies that advertise their high-priced Diabetic Nerve Pain medications on TV, when a very inexpensive vitamin might be the solution to eliminating your discomfort.
DO NOT CHANGE ANY OF YOUR MEDICATIONS BECAUSE OF WHAT YOU READ HERE, and, if you think the Methylcobalamin might reduce or eliminate any nerve pain that you do experience, PLEASE DISCUSS YOUR FEELINGS WITH YOUR DOCTOR AND/or arrange for a Vitamin B-12 deficiency test first!
(One might think that the best solution for eliminating diabetic nerve pain would be to stop taking Metformin. Unfortunately, there is no cure for Diabetes, and until one is found I will have to continue taking this drug. On the upside, I have been able to reduce my weight by 30 lbs this year, and consequently able to cut my dosage of Metformin by 25%).