@article{oai:repo.qst.go.jp:00045147,
 author = {Arakawa, Ryosuke and Ito, Hiroshi and Takano, Akihiro and Takahashi, Hidehiko and Morimoto, Takuya and Sassa, Takeshi and Ohta, Katsuya and Kato, Motoichiro and Okubo, Yoshiro and Suhara, Tetsuya and 荒川 亮介 and 伊藤 浩 and 高野 晶寛 and 高橋 英彦 and 森本 卓哉 and 佐々 毅 and 加藤 元一郎 and 大久保 善朗 and 須原 哲也},
 issue = {2},
 journal = {Psychopharmacology},
 month = {Apr},
 note = {Rationale Paliperidone ER is a novel antipsychotic drug in an
extended-release (ER) formulation.As with all antipsychotics,
careful dose setting is necessary to avoid side effects.
Objectives In this study, we measured striatal and extrastriatal
dopamine D2 receptor occupancy during paliperidone
ER treatment in patients with schizophrenia using
positron emission tomography (PET) to compare regional
occupancy and to estimate the optimal dose.
Materials and methods Thirteen male patients with schizophrenia
participated in this 6-week multiple-dose study. Six
of them took 3 mg of paliperidone ER per day, four took
9 mg, and three took 15 mg. Two to 6 weeks after first drug
intake, two PET scans, one with [11C]raclopride and one
with [11C]FLB 457, were performed in each patient on the
same day. The relationship between the dose or plasma
concentration of paliperidone and dopamine D2 receptor
occupancy was calculated.
Results The dopamine D2 receptor occupancies in the
striatum measured with [11C]raclopride and the temporal
cortex measured with [11C]FLB 457 were 54.2–85.5% and
34.5–87.3%, respectively. ED50 values of the striatum and
temporal cortex were 2.38 and 2.84 mg/day, respectively.
There was no significant difference in dopamine D2 receptor
occupancy between the striatum and the temporal cortex.
Conclusions The data from this study suggest that paliperidone
ER at 6–9 mg provides an estimated level of
dopamine D2 receptor occupancy between 70–80% and
that the magnitude of dopamine D2 receptor occupancy is
similar between the striatum and temporal cortex.},
 pages = {229--235},
 title = {Dose-finding study of paliperidone ER based on striatal and extrastriatal dopamine D2 receptor occupancy in patients with schizophrenia},
 volume = {197},
 year = {2008}
}