Naltrexone-Bupropion Versus Placebo-Bupropion for Weight Loss in Schizophrenia

A Pilot Trial of Naltrexone-Bupropion Combination Versus Placebo Combined With Bupropion for Weight Loss in Comorbid Schizophrenia

The purpose of this study is to determine the efficacy of combining open-label extended release bupropion (flexible dosing up to 450mg target) and naltrexone (37.5mg) versus Bupropion and placebo along with a daily 500 calorie reduction diet recommendation for weight and health risk reduction in 40 overweight/obese individuals with schizophrenia.

The combination of naltrexone with noradrenaline/dopamine reuptake blocker bupropion has been developed and FDA-approved for the treatment of obesity in the general population. Naltrexone does not normally produce weight loss in humans and bupropion produces modest weight loss, however the combination produces clinically significant weight loss, which appears to be more than the sum of its components would otherwise produce separately. Of interest to us, the combination has been shown to be effective for clinically significant weight loss in obese subjects with type 2 diabetes as well. Registration studies by the manufacturer of the combination pill excluded antipsychotic medication users, thus we have no information on the potential effectiveness of the combination in this population. Both naltrexone and bupropion are commonly used in psychiatry, naltrexone for co-morbid alcohol addiction, and bupropion for co-morbid depression and/or cigarette addiction. This is a 16-week pilot trial of 37.5mg naltrexone/placebo added to extended release bupropion in flexible dosing (150mg to 450mg) and a daily 500 calorie reduction diet recommendation for subjects with schizophrenia and obesity. A dose of 37.5mg is similar to the FDA-approved combination dose for naltrexone. However, based on our experience with bupropion, we have chosen to use bupropion in an un-blinded manner and reach the target dose of 450mg based on tolerance of the individual subject over the initial 3-week period.

Changes to the study since registration:

The study was initially registered with 3 arms (Naltrexone vs Bupropion vs Placebo)- whereas the original intent was always supposed to be a 2 armed study (Naltrexone vs Placebo- each with Bupropion included)- this was corrected when the results of the terminated study were entered. In addition, there was an initial intent to include diabetics in the study, but this was later removed as well.

Inclusion Criteria

1. Age 18 to 75
2. Meet DSM-IV criteria for schizophrenia or schizoaffective disorder based on SCID interview (If bipolar-schizoaffective: need to be adequately stabilized on a mood stabilizer and show no mania history for the past one year, as confirmed by study psychiatrist and patient's clinician)
3. Body Mass Index (BMI) of 28 and over
4. On a stable dose of antipsychotic medication; i.e. at least one month with no dose change, and three months from an antipsychotic switch
5. Deemed to be symptomatically stable by the clinical staff in the last two months
6. Over 7% total body weight increase on antipsychotics for subjects within first year of illness

Exclusion Criteria

1. Meet criteria for current opiate abuse or dependence (confirmed by positive urine drug screen for opiates or, if suspected by study doctor via patient history and or suspicion of occult opiate use.) Note: All subjects will be screened for drugs, not only those suspected of opiate use.
2. A history of seizures in the past five years (confirmed through chart review and discussion with patient's clinician)
3. Meet DSM criteria for Bipolar Disorder
4. History of mania in the past one year (confirmed through chart review and discussion with patient's clinician)
5. Uncontrolled hypertension
6. Insulin dependent diabetes mellitus
7. Current history of dementia, mental retardation
8. Not capable of giving informed consent for participation in the study
9. Women who are pregnant or breast-feeding
10. Physical conditions affecting body weight (e.g. Cushing's disease, polycystic ovary syndrome)
11. Severe liver dysfunction, (serum aminotransferases greater than three times normal), acute infectious hepatitis, liver failure.
12. History of glaucoma.