quetiapine-fumarate and epidepride

Selective action at limbic cortical dopamine D(2)-like receptors could mediate atypical antipsychotic efficacy with few extrapyramidal side-effects.. To test the hypothesis that quetiapine has 'limbic selective' D(2)/D(3) receptor occupancy in vivo.. The high-affinity D(2)/D(3) ligand [(123)I]-epidepride and single photon emission tomography were used to estimate D(2)/D(3) specific binding and an index of relative percentage D(2)/D(3) occupancy in striatal and temporal cortical regions for quetiapine-treated patients (n=6). Quetiapine-, and previously studied typical-antipsychotic- and clozapine-treated patients were compared.. Mean (s.d.) relative percentage D(2)/D(3) receptor occupancy by quetiapine was 32.0% (14.6) in striatum and 60.1% (17.2) in temporal cortex (mean daily dose 450 mg: range 300-700 mg/day). Quetiapine treatment resulted in limbic selective D(2)/D(3) blockade similar to clozapine and significantly higher than typical antipsychotics.. Preliminary data suggest that limbic selective D(2)/D(3) receptor blockade is important for atypical drug action.

Topics: Adult; Antipsychotic Agents; Benzamides; Clozapine; Corpus Striatum; Dibenzothiazepines; Female; Humans; Iodine Radioisotopes; Male; Middle Aged; Pyrrolidines; Quetiapine Fumarate; Receptors, Dopamine D2; Receptors, Dopamine D3; Temporal Lobe; Tomography, Emission-Computed, Single-Photon