I have to say that the diabetic nurse did mention this when I was prescribed metformin and said I should also read the leaflet and go back if I thought I had any of the side effects, but she also said they would test me later on as well. Given I'm on a relatively low dose of the stuff I cant say if this drug would cause B12 deficiency in me, however after a month I started taking a supplement every day just to make sure there were no problems.
So I've been taking B12 since November and 2 weeks ago after my latest round of blood tests I saw the Doc on another matter and he asked what vitamin supplements I was taking, so I said just multivitamins and he said 'not extra B12 then'? to which I said I was. He then showed my the levels on the computer and the B12 was like nearly off the chart and way too high. Needless to say he told me to stop taking it because I did not need it. I explained why I was taking it and he said I was wasting my money and any deficiency would be picked up in my routine tests anyway.
