I don't know much these days but this I DO know. SSRI's can give you diarrhea(geez, I can't spell either) and the heart skipping a beat thing. So can fibro...so can anxiety. I have the other problem with Lexapro...constipation. But I have a friend on Zolfot and she has the opposite affect. My heart skips beats almost every day. The sensation is annoying but not dangerous, as long as you have been checked out....which it sounds like you have.
As far as magnesium, I am allergic to nuts and legumes so I know I don't get enough in my diet. I'm glad I read this post because I'm going to up my dose and take the malic acid with it. I hope it helps this buzzing and tingling.
donna