Removal of phenobarbital during continuous cycling peritoneal dialysis in a child

A 2.5-year-old child receiving phenobarbital for a history of seizures while on continuous cycling peritoneal dialysis (CCPD) had persistent subtherapeutic serum levels despite progressive dosage increases. Phenobarbital concentration was measured in the peritoneal dialysate effluent and peritoneal clearance was calculated. Thirty-five percent of the total phenobarbital daily dose was being removed through 24-hour CCPD. Our findings were consistent with previous reports of 40% and 50% phenobarbital removal during continuous ambulatory peritoneal dialysis and acute peritoneal dialysis, respectively. In addition, phenobarbital clearance was greater during the period when more exchanges were done compared with the period when patient went through one cycle with a longer dwell time. Based on these preliminary data, it seems that larger dosages of phenobarbital are necessary in patients undergoing continuous peritoneal dialysis, and that the amount removed can differ significantly depending on the number of cycles.