Metformin
"Been taking Metformin for type 2 diabetes for more than 10 years.  Over the last five years my memory has gotten so bad that I almost can't function at work, I am dizzy, anxious, cold, and often confused.  My doctor said it was not due to the Metformin.  I lowered my dose myself and the coldness stopped and other symptoms improved slightly.  A year later they were even worse.  I cut my pills in half to reduce my dose again, and most of the symptoms went away.  Now that I have been on this reduced dose a while, the symptoms are slowly coming back.  I won't be taking Metformin any more.  It is a terrible way to live not ring able to remember what someone just said to you, where you left off counting, or how to get to the store.  I am only 44."