Relationship between plasma risperidone and 9-hydroxyrisperidone concentrations and clinical response in patients with schizophrenia

E. Spina, A. Avenoso, G. Facciolà, M. Salemi, M. G. Scordo, M. Ancione, A. G. Madia, E. Perucca

Research output: Contribution to journalArticlepeer-review


Rationale: Evaluation of relationships between serum antipsychotic drug concentrations and clinical response may provide valuable information for rational dosage adjustments. For risperidone, this relationship has been little investigated to date. Objective: To assess the relationship between plasma concentrations of risperidone and its active 9-hydroxy-metabolite (9-OH-risperidone) and clinical response in schizophrenic patients who experienced an acute exacerbation of the disorder. Methods: Forty-two patients (30 males, 12 females, age 24-60 years) were given risperidone at dosages ranging from 4 to 9 mg/day for 6 weeks. The design of the study was open and risperidone dosage could be adjusted individually according to clinical response. Steady-state plasma concentrations of risperidone and its 9-hydroxymetabolite were measured after 4 and 6 weeks using a specific HPLC assay. Psychopathological state was assessed at baseline and at weeks 2, 4, and 6 by means of the positive and negative syndrome scale (PANSS), and patients were considered responders if they showed a greater than 20% reduction in total PANSS score at final evaluation compared with baseline. Results: Mean plasma concentrations of risperidone, 9-OH-risperidone, and active moiety (sum of risperidone and 9-OH-risperidone concentrations) did not differ between responders (n=28) and non-responders (n=14). No correlation between plasma levels and percent decrease in total PANSS score was found for risperidone (rs=-0.187, NS), 9-OH-risperidone (rs=0.246, NS), and active moiety (rs=0.249, NS). Active moiety concentrations in plasma were higher (P

Original languageEnglish
Pages (from-to)238-243
Number of pages6
Issue number2
Publication statusPublished - 2001


  • 9-Hydroxy-risperidone
  • Parkinsonism
  • Plasma concentration
  • Risperidone
  • Schizophrenia
  • Therapeutic drug monitoring

ASJC Scopus subject areas

  • Pharmacology


Dive into the research topics of 'Relationship between plasma risperidone and 9-hydroxyrisperidone concentrations and clinical response in patients with schizophrenia'. Together they form a unique fingerprint.

Cite this