Carbamazepine clearance in hemodialysis and hemoperfusion

A 47-year-old woman with endstage renal disease and dialysis-induced encephalopathy was being treated with carbamazepine for myoclonus. Her carbamazepine serum concentration appeared to be therapeutic at 5.1 micrograms/ml. She experienced a seizure while on hemodialysis/hemoperfusion that was possibly related to the removal of carbamazepine during dialysis. The elimination of carbamazepine on a dialysis day was compared with elimination on a nondialysis day. The half-life and apparent clearance were the same for each day, indicating that hemodialysis/hemoperfusion had little effect on the overall removal of carbamazepine from the body. The possible reasons for this lack of effect are discussed.