Targeted Naltrexone for Problem Drinkers

Inclusion Criteria: Male and female outpatients 18-70 years of age. Participants will have an average weekly ethanol consumption of >=24 standard drinks for men, or >=18 standard drinks for women (i.e., substantially in excess of non-hazardous drinking levels). Participants will be able to read English at the eighth grade or higher level and show no evidence of significant cognitive impairment. If a woman of child-bearing potential (i.e., who has not had a hysterectomy, bilateral oophorectomy, tubal ligation or who are less than two years postmenopausal), participant must be non-lactating, practicing a reliable method of birth control, and have a negative serum pregnancy test prior to initiation of treatment. Participants will be willing to provide signed, informed consent to participate in the study (including a willingness to reduce drinking to non-hazardous levels). Exclusion Criteria: Participants who have a current, clinically significant physical disease or abnormality on the basis of medical history, physical examination, or routine laboratory evaluation, including total bilirubin elevations of >110% or ALT or AST elevations >300% the upper limit of normal or have a diagnosis of Hepatitis B or C infection or AIDS (given the potential for adverse effects of naltrexone on liver function). Participants who have a serious psychiatric illness (i.e., schizophrenia, bipolar disorder, severe major depression, panic disorder, borderline personality states, organic mood or mental disorders, or substantial suicide or violence risk) on the basis of history or psychiatric examination. Participants who have a current Diagnostic and Statistical Manual of Mental Disorders 4th ed (DSM-IV) diagnosis of drug dependence (other than nicotine dependence) or a lifetime DSM-IV diagnosis of opioid dependence. Participants who have a current DSM-IV diagnosis of alcohol dependence that is clinically severe. Participants who have used opioids or other psychoactive medications regularly in the month prior to study enrollment. Participants who have a history of hypersensitivity to naltrexone. Participants who are considered by the investigators to be an unsuitable candidate for receipt of an investigational drug.