Well, to be honest I don't know if you will notice anything on 200mg, because it isn't at the therapeutic level which I've read is supposed to be around .8-1.2 mEq/L. But I've also read that .6-1.2 mEq/L is considered therapeutic. (I read that for some people 300mg works, too so I suppose 200 can...) Is your doctor planning on keeping you at 200? They could mean that she is testing whether or not you can tolerate the medicine. It can also mean it's being used to strengthen another med you're taking so you only need a small dose. However, my knowledge on how medications work are pretty limited so you should ask her.

Since I'm a bit paranoid I always interrogate my pdoc about what I am taking. I have problems trusting them because they're not taking the medication and I want to be sure that I'm taking it for a valid reason.

I hope you have a good day, Suga!