D1-, D2-, and 5-HT2-receptor occupancy in clozapine-treated patients.
Positron emission tomography (PET) and selective radioligands were used to determine central D1- and D2-dopamine- and 5-HT2-receptor occupancy in clozapine-treated patients with schizophrenia. In 16 patients, the mean D2-receptor occupancy was 47% (range, 20%-67%), which is lower than that previously demonstrated in patients treated with classical neuroleptics (range, 70%-89%). In 11 patients, the mean D1-receptor occupancy was 44% (range, 33%-59%), which is high when compared with that for classical neuroleptics. In a group of 5 patients, including some treated with low doses of clozapine, the mean 5-HT2-receptor occupancy was a high 89% (range, 84%-94%). By comparison to classical neuroleptics, clozapine is atypical with regard to central binding characteristics in the brain of treated patients.
Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden.
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Farde
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Nordström
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Nyberg
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Halldin
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Sedvall
D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D002250:Carbon Radioisotopes; D003024:Clozapine / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011954:Receptors, Dopamine / Q000187:drug effects* / Q000378:metabolism; D011985:Receptors, Serotonin / Q000187:drug effects* / Q000378:metabolism; D012559:Schizophrenia / Q000188:drug therapy / Q000378:metabolism; D014055:Tomography, Emission-Computed
D002250:Carbon Radioisotopes; D011954:Receptors, Dopamine; D011985:Receptors, Serotonin; D003024:Clozapine