A Study of the Effects of Risperidone and Olanzapine on Blood Glucose (Sugar) in Patients With Schizophrenia or Schizoaffective Disorder

A Six-month, Double-blind, Randomized, International, Multicenter Trial to Evaluate the Glucoregulatory Effects of Risperidone and Olanzapine in Subjects With Schizophrenia or Schizoaffective Disorder

Status

Completed

Phases

Phase 4

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT00236379

Enrollment

Registered

2005-10-12

Start date

Unknown

Completion date

2003-08-31

Last updated

2011-05-17

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Diabetes Mellitus, Schizophrenia

Keywords

schizophrenia, blood glucose, glucose metabolism, diabetes mellitus, risperidone, olanzapine

Brief summary

The purpose of this study is to assess and compare how risperidone and olanzapine, two antipsychotic medications, affect the regulation of glucose (sugar) in the body.

Detailed description

The newer antipsychotic medications risperidone and olanzapine effectively treat schizophrenia and related disorders, and they may cause fewer side effects than the older antipsychotic drugs do. However, some of the newer antipsychotic medications could have a negative effect on the regulation of blood glucose (sugar) in the body. This negative effect could make the patient gain weight and even develop diabetes mellitus. This randomized, double-blind study will assess and compare how risperidone and olanzapine affect the regulation of glucose in the body in patients with schizophrenia and schizoaffective disorder. Patients will be randomly assigned to receive risperidone (target oral dose of 6 milligrams per day) or olanzapine (target oral dose of 20 milligrams per day) for 6 months. Repeat laboratory measurements will be performed and questions will be asked of the patients to evaluate the safety and effectiveness of the drugs. The primary laboratory test used to assess the patient's regulation of blood glucose will be the Disposition Index derived from the Frequently Sampled Intravenous Glucose Tolerance Test. Risperidone 2 milligram oven-encapsulated tablets taken orally once a day for 6 months; olanzapine 5 milligram tablets taken orally once a day for 6 months

Interventions

DRUGOlanzapine

Target oral dose of 20 milligrams per day for 6 months

DRUGRisperidone

Target oral dose of 6 milligrams per day for for 6 months

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Masking

DOUBLE

Eligibility

Sex/Gender

ALL

Age

18 Years to 65 Years

Healthy volunteers

Inclusion criteria

* Diagnosis of schizophrenia or related disorder * stable with respect to disease symptoms and other medical conditions * would benefit from this type of antipsychotic drug * if female, using birth control.

Exclusion criteria

* Patients who are delirious, bipolar, severely mentally retarded, or suicidal * psychiatric diagnosis of disease unrelated to schizophrenia * presence of stroke, brain tumor, Parkinson's Disease, or diseases that affect blood glucose control * history of diabetes * long or recent history of taking risperidone, olanzapine, quetiapine, clozapine, or investigational drugs * recent history of unstable thyroid function * if female, not using birth control * abusing drugs or alcohol.

Design outcomes

Primary

Measure	Time frame
Change in the Disposition Index derived from the Frequently Sampled Intravenous Glucose Tolerance Test (which shows how the body regulates glucose)	Up to 6 months

Secondary

Measure	Time frame
Changes in measurements of metabolism and glucose regulation; changes in results of tests and questionnaires evaluating the effectiveness and safety (including laboratory tests and anthropomatic measurements) of medications used to treat schizophrenia	Up to 6 months

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026