Patient: I had a B12 overdose and need to know what to do to reverse it. I has a very fast heart rate which now has settled, but the upper part of my eyes are blood red, like i broke a vessel. What can i take to get myself back to normal and why did this happen. i only took 3 ius
Doctor: Vitamin B12 overdose is rare as this vitamin even in large doses is generally non toxic and safe. This is because of the method in which it is metabolised. In order to have a systemic effect it needs to bind to something called an intrinsic factor which is produced in the stomach. Once the Intrinsic factor is saturated there is no more binding and thus no more absorbtion of vitamin B12 and thus toxicity is rare. In rare cases when there are symptoms it usually manifests as long term effects like cancer etc and not acute symptoms. The symptoms you are experiencing may be due to various other causes and need to be investigated seperately. All the best.