Side Effects

Hi,

Recently had a parathyroid operation and it was determined that my magnesium level was a little low. My dr. asked me to take 400mg of magnesium oxide twice a day. After a couple of weeks I'm feeling somewhat dizzy and with some tingling in my fingertips. Can this be an effect of taking this. I'm also a kidney transplant recipient and I'm taking a bunch of other meds but nothing new for quite some time.

Thanks,
John