OBJECTIVES: There are four FDA-approved alcoholism medications: disulfiram, naltrexone, acamprosate, and extended-release naltrexone (XR-NTX). This study used observational data to evaluate the utilization and cost outcomes of insured patients treated with alcohol medications or no medication. METHODS:  Data were from Thomson Reuter’s MarketScan Commercial insurance claims database which contains information from millions of enrollees annually. Outcomes were measured six months after index and included medication possession ratio (MPR), detoxification admissions and days, alcohol-related admissions and days, ED visits, psychiatric and substance abuse outpatient visits and charges for detoxification and alcohol-related inpatient stays.  Two sets of analyses were conducted: 1) Persons with an alcohol use disorder and no use of any alcohol medication (n=4,047) were compared to persons with an alcohol use disorder and use of any of the four medications (n = 4,730).  The samples were propensity-score matched on demographics, clinical characteristics and prior use of alcohol and psychiatric services, and 2) The four medications were compared (XR-NTX n = 275; naltrexone n = 2064 acamprosate n = 5068; disulfiram n = 2076) using inverse probability weighting. RESULTS:  The probability of any detoxification admission, alcohol-related admission, and ED visit and a substance abuse or psychiatric visit was significantly higher among no medication users than medications users.  XR-naltrexone users had a significantly higher MPR than acamprosate users. Patients using any medication had fewer detoxification days and alcoholism-related inpatient days.  Among medication users, XR-NTX was associated with significantly lower detoxification costs (per 1000 patients over 6 months) versus oral naltrexone, disulfiram and acamprosate (Detox: $0.60-million vs. $1.48-million, $1.08-million, $1.40-million; respectively; P<0.01 for XR-NTX vs. naltrexone and acamprosate). CONCLUSIONS:  Individuals receiving alcoholism medications had significantly and substantially lower detoxification and hospitalization utilization rates than similar patients who received no medication. Of the approved medications, XR-TX had lower costs for detoxification and alcoholism hospitalization days.