Introduction: This systematic review of therapeutic drug monitoring (TDM) identifies three long-acting injectable (LAI) risperidone formulations. Areas covered: Limited data is available on two formulations (RBP-7000 and in Situ Microparticle), but 20 TDM articles on the microsphere formulation were found. Risperidone TDM includes the serum concentrations of risperidone and its active metabolite, 9-hydroxyrisperidone, used for calculating: 1) the risperidone/9-hydroxyrisperidone (R/9-OH-R) ratio (a measure of CYP2D6; values >1 are indicative of a CYP2D6 poor metabolizer) and 2) the total risperidone concentration-to-dose (C/D) ratio (a measure of risperidone clearance with a normal value around 7 in oral risperidone). The weighted mean R/9-OH-R ratio was 0.48 (approximately twice that of oral risperidone TDM) in a combined analysis from 329 patients in 6 risperidone LAI studies without major confounders. The total C/D ratios from 297 patients in 6 risperidone LAI studies ranged from 7.4 to 9.7 ng/ml/mg/day with a weighted mean of 8.8 ng/ml/mg/day. Expert commentary: Clinicians using TDM for risperidone LAI microsphere formulation need to: 1) consider steady state to be reached ≥ 6 weeks after the first injection, 2) pay attention to a) co-medications with inducers/inhibitors, b) severe inflammations/infections, and c) hepatic/renal impairment, and 3) use Castberg’s recommendation to calculate risperidone dosing.
|Number of pages||17|
|Journal||Expert Review of Clinical Pharmacology|
|State||Published - Sep 2 2017|
Bibliographical notePublisher Copyright:
© 2017 Informa UK Limited, trading as Taylor & Francis Group.
- Antipsychotic agents/administration & dosage
- delayed-action preparations
- drug monitoring
- risperidone/administration & dosage
- risperidone/therapeutic use
- schizophrenia/drug therapy
ASJC Scopus subject areas
- Pharmacology, Toxicology and Pharmaceutics (all)
- Pharmacology (medical)