Optimal Dosing of Risperidone and Olanzapine in the Maintenance Treatment for Patients With Schizophrenia and Related Psychotic Disorders: A Retrospective Multicenter Study

Therapeutic Drug Monitoring of Olanzapine and Cytochrome P450 Genotyping in Nonsmoking Subjects

BACKGROUND

The relationship between a daily dose of olanzapine, its serum concentration, and the genotype of young nonsmoking men treated for schizophrenia or schizophreniform disorder was investigated in day-to-day clinical practice. Pharmacogenetics was also examined for the selected patients.

METHODS

A total of 49 participants were recruited as in-patients at the Mental Health Research Center (Moscow, Russia). Inclusion criteria were patients who had been diagnosed with schizophrenia or schizoaffective disorder (following DSM-IV guidelines) and were being treated with OLZ. A prospective, observational, open-study design was implemented. In line with the literature, patients were only included if they attained steady-state OLZ concentrations lasting for at least 8 days. A liquid chromatographic-tandem mass spectrometric method was developed for analyzing OLZ in human serum. The single cytochrome P450 polymorphisms were genotyped using an amplifier real-time polymerase chain reaction system following standard protocols.

RESULTS

Evidence indicating that CYP2D6 polymorphism has a significant (P = 0.046) effect on the pharmacokinetics of olanzapine was obtained, confirming the beneficial effects of therapeutic drug monitoring (TDM) for olanzapine.

CONCLUSIONS

TDM should therefore be used as a standard care during olanzapine therapy. TDM is also useful in assessing adherence and may have a role in limiting olanzapine dosage geared at minimizing the risk of long-term toxicity.

Specific Anti-hostility Effects of Atypical Antipsychotics in Persons with Schizophrenia: From Clozapine to Cariprazine

LEARNING OBJECTIVE

After participating in this activity, learners should be better able to:• Evaluate the anti-hostility effects of available atypical antipsychotic agents.

ABSTRACT

In addition to hallucinations and delusions, persons with schizophrenia may exhibit hostility. In clinical trials of antipsychotics, hostility is routinely measured as part of rating scales such as the Brief Psychiatric Rating Scale or Positive and Negative Syndrome Scale. The availability of the atypical antipsychotic clozapine in 1989 led to the observation that it is possible to have a treatment effect on hostility that is independent of the treatment effect on hallucinations or delusions, and independent of general sedative effects. The data supporting this notion of a specific anti-hostility effect are the most robust for clozapine as the data include specifically designed randomized, controlled clinical trials. A specific anti-hostility effect is also observable to various degrees with most of the other atypical antipsychotics, as evidenced in post hoc analyses of clinical trials originally conducted for regulatory purposes, supplemented by post hoc analyses of large effectiveness trials. The generalizability of these studies, however, may be limited. Participants in these trials were not selected for aggressive and hostile behavior. Some of the studies also excluded patients with substance use disorders. The latter is particularly important because alcohol and substance use are well known to increase risk for hostility and aggression. Nevertheless, the repeated demonstrations of the specificity of an anti-hostility effect (in terms of statistical independence of effects on other positive symptoms and of sedation) are of potential clinical importance.

Dose reduction of risperidone and olanzapine can improve cognitive function and negative symptoms in stable schizophrenic patients: A single-blinded, 52-week, randomized controlled study

BACKGROUND

The long-term effects of dose reduction of atypical antipsychotics on cognitive function and symptomatology in stable patients with schizophrenia remain unclear. We sought to determine the change in cognitive function and symptomatology after reducing risperidone or olanzapine dosage in stable schizophrenic patients.

METHODS

Seventy-five stabilized schizophrenic patients prescribed risperidone (≥4 mg/day) or olanzapine (≥10 mg/day) were randomly divided into a dose-reduction group ( n=37) and a maintenance group ( n=38). For the dose-reduction group, the dose of antipsychotics was reduced by 50%; for the maintenance group, the dose remained unchanged throughout the whole study. The Positive and Negative Syndrome Scale, Negative Symptom Assessment-16, Rating Scale for Extrapyramidal Side Effects, and Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery were measured at baseline, 12, 28, and 52 weeks. Linear mixed models were performed to compare the Positive and Negative Syndrome Scale, Negative Symptom Assessment-16, Rating Scale for Extrapyramidal Side Effects and MATRICS Consensus Cognitive Battery scores between groups.

RESULTS

The linear mixed model showed significant time by group interactions on the Positive and Negative Syndrome Scale negative symptoms, Negative Symptom Assessment-16, Rating Scale for Extrapyramidal Side Effects, speed of processing, attention/vigilance, working memory and total score of MATRICS Consensus Cognitive Battery (all p<0.05). Post hoc analyses showed significant improvement in Positive and Negative Syndrome Scale negative subscale, Negative Symptom Assessment-16, Rating Scale for Extrapyramidal Side Effects, speed of processing, working memory and total score of MATRICS Consensus Cognitive Battery for the dose reduction group compared with those for the maintenance group (all p<0.05).

CONCLUSIONS

This study indicated that a risperidone or olanzapine dose reduction of 50% may not lead to more severe symptomatology but can improve speed of processing, working memory and negative symptoms in patients with stabilized schizophrenia.