title: Relationship between plasma concentration levels of risperidone and clinical effects in the treatment of delirium.
abstract: The present study aimed to examine the relationship between plasma concentration levels of risperidone and clinical effects in the treatment of delirium. We conducted a prospective, open-label, flexible-dose study of risperidone oral solution. Ten patients with delirium were assessed using Delirium Rating Scales. Plasma concentration levels of risperidone were measured 30 min after the first administration of a 0.5 mg dose. Two patients with high plasma levels had adverse effects and one patient with the lowest plasma level did not achieve remission; the remaining seven patients achieved remission without any adverse effects. A highly significant negative correlation was observed in these responders without adverse effects between the plasma levels and durations of treatment until remission (r=-0.861, P=0.0095). The plasma concentration level of risperidone at 30 min after the first 0.5 mg dose may be a favourable response predictor in the treatment of delirium. Further studies in larger samples are needed to verify this preliminary finding.
authors.affiliation: Department of Psychiatry, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Toda
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kusumi
authors.forename: Yukiya
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Koichi
authors.initials: K
authors.lastname: Ito
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Koyama
mesh_terms: D000284:Administration, Oral; D000368:Aged; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D003693:Delirium / Q000097:blood / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D018967:Risperidone / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D013997:Time Factors
chemical_list: D014150:Antipsychotic Agents; D018967:Risperidone