I have had problems with my potassium for the past eight years. Spent several times in the ER getting potassium IV's. The first time I had trouble, I didn't know that I had lupus yet, but had been have a lot of pancreas troubles. They said that that shouldn't have caused it.
When I had trouble it really affected my heart, my EKG, a lot of palpatations and just generally feeling really bad.
I take presc. potassium every day and have since that first time I had trouble.
My dr. thinks it could be malabsorbtion. Who knows!
Hope that helps!