Carbamazepine과 Phenobarbital이 항정상태의 혈청 Haloperidol 농도에 미치는 영향

Effects of Carbamazepine and Phenobarbital on the Steady-State Serum Haloperidol Levels

To investigate the effect of adding carbamazepine or phenobarbital on the steady-state haloperidol levels, we selected 15 chronic psychotic patients who had been in the same psychiatric ward for a minimum of 3 months. All were maintained daily 20mg of haloperidol for at least 2 weeks before adding carbamazepine or phenobarbital. Either of these two agents was added to the ongoing haloperidol medication and rapidly increased to therapeutic dosage within 3 days. After plateau dosage was achieved, it was maintained for the next 4 days. The serum haloperidol levels of 7 patients on carbamazepine plus haloperidol and 8 patients on phenobarbital plus haloperidol were determinded with high-performance liquid chromatography before and after the 7 days of concomitant medication. Additionally the clinical changes noted during this period were rated on the Brief Psychiatric Rating Scales. The percent decrease in the steady-state haloperidol levels due to adding carbamazepine for 7 days was between 18^ and 64%, and was between 5% and 52%, due to adding phenobarbital. Based upon this study’ s preliminary findings, the effects of these two agents on serum haloperidol levels were noted to occur within one week. Clinical worsenings found in some patients on carbamazepine plus haloperidol, but it was difficult to document whether carbamazepine-induced reductions of serum haloperidol levels were the significant factors in the clinical changes.