The therapeutic dosage depends on attaining a therapeutic blood level. Generally, the dosage
range is 400–1,200 mg/day. Blood levels
of carbamazepine should be monitored weekly for the first 4 weeks to ensure that adequate levels are achieved to produce the therapeutic response."
You could print out that document and bring it in and ask your doc why he thinks you were taking too much tegretol, especially since the reduction is causing problems.