The main purpose of this study is to determine whether the opioid antagonist naltrexone is helpful in ameliorating the weight gain and other adverse metabolic side effects experienced by schizophrenic patients taking the second generation antipsychotic (SGA) Zyprexa. Schizophrenics may have an altered/enhanced endogenous opioidergic drive, and because of this, normally painful stimuli will be sensed as less painful in schizophrenics vs. healthy controls. A secondary hypothesis for this study is that naltrexone augmentation of Zyprexa will normalize subjective pain ratings. Our tertiary objective is to examine the safety and tolerability of naltrexone in Zyprexa-treated patients with schizophrenia.
Zyprexa is one of the most commonly prescribed second generation antipsychotic drugs (SGAs), but its (and other SGA's) side effects contribute to the development of obesity and to the "Metabolic Syndrome." Both conditions, which are more prevalent even in unmedicated schizophrenic patients, are associated with increased cardiovascular morbidity and mortality. The mechanisms of these side effects are likely to be multifactorial and to involve peripheral and central factors alike. The present proposal asks a fundamental question: How the endogenous opioidergic systems are involved in Zyprexa-induced obesity and in related metabolic disturbances. We further hypothesize that if the excess of central opioid activity creates metabolic problems for patients, it is reasonable to expect amelioration of the symptoms through blockade of opioid receptors. The proposed project is designed to test this hypothesis by complimenting clinical psychopharmacology with pain medicine research and functional magnetic resonance imaging (fMRI) to empirically measure clinical outcomes of Zyprexa pharmacotherapy augmentation with the opioid receptor antagonist, naltrexone. Our objectives and hypotheses are as follows: to determine the effects of naltrexone on weight gain, metabolic (e.g., cholesterol, lipids, insulin, leptin and glucose levels), anthropometric and nutritional characteristics in Zyprexa treated schizophrenic patients, to examine the effects of naltrexone on subjective pain ratings, and to investigate the safety and tolerability of naltrexone in Zyprexa-treated schizophrenic patients.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SUPPORTIVE_CARE
Masking
DOUBLE
Enrollment
30
50mg naltrexone, 1 tablet a day for 12 weeks.
lactose placebo, 1 capsule every day for 12 weeks
McLean Hospital
Belmont, Massachusetts, United States
Weight and Body Mass Index
Time frame: 12 weeks
Subjective pain ratings, fMRI activations in the a priori selected ROIs, waist, waist/hip ratio, fasting blood glucose, LDL cholesterol, HDL cholesterol, triglycerides, fat body mass, insulin, leptin, and food intake
Time frame: 12 weeks
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