DETERMINATION OF CLOZAPINE IN SERUM BY RADIORECEPTOR ASSAY VERSUS HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY - POSSIBLE DETECTION OF HYDROXY-METABOLITES

Clozapine is an antipsychotic drug with few extrapyramidal motor side- effects, used to treat schizophrenia which is resistant to classical n euroleptic therapy. This report shows that norclozapine but not clozap ine-N-oxide has the same D2 receptor affinity as clozapine. Assay resu lts suggest a bimodal distribution which may be explained by CYP1A2 po lymorphism. Extensive metabolizers could produce other active metaboli tes, probably other hydroxy-clozapine derivatives.