Longitudinal changes in antipsychotic dose in patients treated with long-acting injectable second-generation antipsychotics

Nozomi Nakajima, Nao Mizoe, Fuminari Misawa, Toru Yamashita, Ryuhei So, Kohei Kitagawa, Kenichi Tanimoto, Yoshiki Kishi, Yasuo Fujii, Hiroyoshi Takeuchi

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Only a few studies have investigated changes in the dose of long-acting injectable second-generation antipsychotics (LAI-SGAs) over the long term in the maintenance treatment of schizophrenia. In this retrospective cohort study, we examined longitudinal changes in antipsychotic dose over a 3-year period in patients with schizophrenia who had been taking LAI-SGAs for at least 1 year. We compared the total daily chlorpromazine equivalent dose of antipsychotics at 12, 24 and 36 months with the baseline dose at 3 months after initiation of LAI-SGAs. We also performed multiple regression analysis to explore factors associated with change in total daily dose 12 months after treatment initiation. A total of 154 patients fulfilled the inclusion criteria. There was no significant difference in total daily antipsychotic dose between 3 months and 12, 24 or 36 months after treatment initiation. Total daily dose was increased in 43 (27.9%), 31 (34.8%) and 22 patients (36.7%) at 12, 24 and 36 months, respectively. Age and total antipsychotic dose at 3 months were significantly negatively associated with change in total daily dose. Antipsychotic dose was basically unchanged during long-term treatment in patients treated with LAI-SGAs in the maintenance phase, although there was an increase in some patients.

Original languageEnglish
Pages (from-to)84-88
Number of pages5
JournalInternational clinical psychopharmacology
Issue number2
Publication statusPublished - 2021 Mar 1


  • antipsychotics
  • dose
  • long-acting injection
  • schizophrenia
  • second-generation antipsychotics

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Pharmacology (medical)


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