Thanks for responding.... my doctor started me on on 150mg per day... then increased to 300mg per day for a couple of days... then finally up to 600mg per day. He gave me no instructions to check my levels at 600mg though. This is the 1st time I am on Lithium and I weigh 105 lbs. so I thought it was weird, but I figured he's the doctor so (hopefully) he knows what he's doing. I'm sure the covering doctor was being extra cautious with his decision. I appreciate that. I have cut back to 300mg and will speak to my dr. about this on Monday.