Determination of pharmacokinetic properties of clozapine and norclozapine in Korean schizophrenia patients.
There is a wide interethnic variance in the pharmacokinetic profile of clozapine (CLZ), but the accumulated data are limited to some regional populations. In this study, we investigated the pharmacokinetic profile of CLZ in Korean patients and examined the association between serum CLZ parameters and clinical outcome. We assessed 78 Korean patients with schizophrenia who had been taking CLZ medication for more than 6 months. The patients were classified into three groups (good, moderate, and poor responders) according to their Clinical Global Impressions-Improvement scores. The serum concentrations of CLZ and norclozapine were 610.7+/-368.4 and 314.5+/-163.0 ng/ml (mean+/-SD), respectively, showing a large interindividual variation that was affected by dose, age, smoking habits, and sex by variable degrees. The pharmacokinetic profiles of Koreans were similar to those observed in Asians but quite different from those in Caucasians. Investigation on clinical responses revealed that the good or moderate responders clinically improved at a relatively low serum CLZ levels, whereas the poor responders showed less improvement despite the higher doses and serum levels. The metabolic ratio of the good responders was 0.65+/-0.20, higher than the poor responders (P=0.033). In this study, we identified a pharmacokinetic profile of CLZ in Korean schizophrenia patients and found a wide interindividual difference affected by various factors.
Lee
Seung-Tae
ST
Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Ryu
Seunghyong
S
Nam
Hee Jung
HJ
Lee
Soo-Youn
SY
Hong
Kyung Sue
KS
D000328:Adult; D000375:Aging / Q000502:physiology; D014150:Antipsychotic Agents / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D003024:Clozapine / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007723:Korea; D008297:Male; D011569:Psychiatric Status Rating Scales; D012044:Regression Analysis; D012189:Retrospective Studies; D012559:Schizophrenia / Q000188:drug therapy / Q000378:metabolism*; D012565:Schizophrenic Psychology; D012907:Smoking / Q000523:psychology; D016896:Treatment Outcome
D014150:Antipsychotic Agents; C058272:norclozapine; D003024:Clozapine