Relationship between plasma concentration levels of risperidone and clinical effects in the treatment of delirium.

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.

A prospective, open-label, flexible-dose study of quetiapine in the treatment of delirium.

BACKGROUND: Delirium is an organic psychiatric syndrome characterized by fluctuating consciousness and impaired cognitive functioning. High-potency typical neuroleptics have traditionally been used as first-line drugs in the treatment of delirium. However, these drugs are frequently associated with undesirable adverse events including extrapyramidal symptoms (EPS). The purpose of the present open-label, flexible-dose study was to provide preliminary data on the usefulness and safety of quetiapine for patients with delirium. METHOD: Twelve patients with DSM-IV delirium were treated with flexible doses of open-label quetiapine (mean +/- SD dosage = 44.9 +/- 31.0 mg/day). To evaluate the usefulness and safety of quetiapine, scores from the Delirium Rating Scale, Japanese version, were assessed every day (for 1 outpatient, at least twice per week), and scores from the Mini-Mental State Examination, Japanese version, and the Drug-Induced Extrapyramidal Symptom Scale were assessed at baseline and after remission of delirium. Data were gathered from April to October 2001. RESULTS: All patients achieved remission of delirium several days after starting quetiapine (mean +/- SD duration until remission = 4.8 +/- 3.5 days). Quetiapine treatment was well tolerated, and no clinically relevant change in EPS was detected. CONCLUSION: Quetiapine may be a useful alternative to conventional neuroleptics in the treatment of delirium due to its rapid onset and relative lack of adverse events. Further double-blind, placebo-controlled studies are warranted.