Talaria, Inc., has designed an adherence tracking and enhancement system, called AGATE, which uses the text messaging and internet capabilities of modern cellular phones to address the problem of medication adherence in clinical care and clinical trial contexts. This trial will evaluate whether AGATE improves medication adherence in the context of a pharmacotherapy trial of naltrexone to treat problem drinking. All participants will be treatment-seeking problem drinkers who will receive naltrexone and medication monitoring over 8 weeks.