Pharmacokinetics of risperidone in different application forms – Comparing long-acting injectable and oral formulations

Georgios Schoretsanitis, Jose de Leon, Ekkehard Haen, Benedikt Stegmann, Christoph Hiemke, Gerhard Gründer, Michael Paulzen

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


We aimed to explore the differences in the pharmacokinetics of risperidone between oral and long-acting injectable (LAI) formulations using a large database of therapeutic drug monitoring (TDM). Plasma concentrations of risperidone (RIS), its active metabolite (9-OH-RIS) and the active moiety (AM) (RIS+9-OH-RIS), their concentration-to-dose (C/D) ratios and ratio of RIS/9-OH-RIS (an index of CYP2D6 metabolic activity) were used to compare patients receiving risperidone orally (n = 851) and those treated with LAI RIS (n = 63). Patients taking CYP inducers or inhibitors or with liver/renal impairment were eliminated. Our study demonstrated that patients on LAI RIS, despite slightly higher RIS doses in the oral group, showed no significant differences in total AM or 9-OH-RIS. Conversely, RIS concentration, RIS C/D ratio and total C/D ratio were slightly higher in the LAI RIS group, reaching significance due to the large sample size. More importantly, the median ratio of RIS/9-OH-RIS was 0.52 in LAI RIS vs. 0.25 in the oral group, providing a significant difference (p < 0.001). After controlling for confounding factors, we replicated the RIS/9-OH–RIS ratio increases in patients with LAI RIS, probably reflecting a decrease in first-pass metabolism. More studies are required to establish the clinical use of TDM for patients on LAI RIS.

Original languageEnglish
Pages (from-to)130-137
Number of pages8
JournalEuropean Neuropsychopharmacology
Issue number1
StatePublished - Jan 2018

Bibliographical note

Publisher Copyright:
© 2017 Elsevier B.V. and ECNP


  • cytochrome P-450 CYP2D6
  • drug monitoring
  • risperidone/administration and dosage
  • risperidone/metabolism
  • risperidone/pharmacokinetics

ASJC Scopus subject areas

  • Pharmacology
  • Neurology
  • Clinical Neurology
  • Psychiatry and Mental health
  • Biological Psychiatry
  • Pharmacology (medical)


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