I take 750mg of Lithium a day, 500mg am and 250mg pm. At times I take higher doses but still spit it as directed by my pdoc. I think Lithium stays in the bloodstream for about 12 hours so splitting it seems logical but there was a time that I took all my 750mg in the am and I noticed no difference in effectiveness. If your pdoc thinks taking it all at once is fine I can't see a problem there. Is it working for you?