Effect of Varenicline on Fixed-Dose Alcohol Administration in Participants With Alcohol Use Disorders

Inclusion Criteria: * 21 years old or older * Able to read and write in English * Smokers and nonsmokers * Meet criteria for alcohol use disorders * Currently enrolled in NCT00580645 Exclusion Criteria: * Any significant current medical or psychiatric conditions that would contraindicate the consumption of alcohol * Significant hepatocellular injury * Positive test results at intake appointments on urine drug screens conducted for opiates, cocaine, or benzodiazepines * Women who are pregnant or nursing * Suicidal, homicidal, or evidence of severe mental illness * Prescription of any psychotropic drug in the 30 days prior to study enrollment * Blood donation within the past 8 weeks * Individuals who are seeking treatment for drinking or smoking or who have attempted to quit drinking or smoking within the past 3 months * Known allergy to varenicline or taking H2blockers * Participation within the past 8 weeks in other studies that involve additive blood sampling and/or interventional measures that would be considered excessive in combination with the current protocol * Subjects likely to exhibit clinically significant alcohol withdrawal during the study