Varenicline + Prazosin for Heavy Drinking Smokers

Inclusion Criteria: 1. at least 18 years of age; 2. current smoker \[quantity of ≥ cigarettes per smoking day, frequency of ≥3 times per week, and urinary cotinine ≥2 on NicAlert dipstick; 3. at least 4 occasions of heavy drinking in the past 30 days \[5 or 4 standard drinks per occasion for males and females, respectively\]; 4. no history of severe alcohol withdrawal syndrome; 5. no new onset of psychiatric illness or psychotropic medications in last 90 days; 6. no severe psychiatric illness \[schizophrenia, bipolar disorder\] or PTSD; 7. no substance dependence other than nicotine, alcohol or marijuana; 8. no medical contraindications for varenicline or prazosin; 9. are willing to take medication and wear portable sleep monitoring devices; 10. no risk for sleep apnea syndrome; 11. able to read and write in English; 12. not interested in quitting smoking immediately. Exclusion Criteria: 1. unable to complete the informed consent; 2. do not meet criteria for heavy drinking; 3. do not meet criteria for current smokers; 4. unable to read/understand English; 5. exhibit serious psychiatric illness (i.e. schizophrenia, bipolar disorder, severe major depression, panic disorder, borderline personality disorder), organic mood or mental disorders by history of psychological examination; 6. meet criteria for alcohol dependence in past 12 months that is clinically severe; 7. meet criteria for drug dependence in the last 12 months aside from marijuana, nicotine and alcohol; 8. are seeking to quit smoking immediately; 9. report current psychosis or suicidality; 10. are a female of childbearing potential who is pregnant, nursing, or not practicing effective contraception (oral, injectable, or implantable contraceptives, intrauterine device, or barrier method with spermicide); 11. exhibit current, clinically significant physical disease or abnormality based on medical history, physical examination, or routine laboratory evaluation including: 1. any unexplained elevations in liver enzymes (i.e. transaminases, bilirubin); 2. clinically significant, unstable cardiovascular disease/uncontrolled hypertension; 3. hepatic or renal impairment; 4. severe obstructive pulmonary disease; 5. diabetes mellitus requiring insulin or certain oral medications (i.e. sulfonylureas) and an A1C hemoglobin test score of \>7 for participants not prescribed these medications; 6. baseline systolic blood pressure higher than 150 mm Hg of diastolic blood pressure higher than 95 mm Hg; (g) are scheduled for cataract surgery; (h) have a diagnosis of narcolepsy; 12. have a history of cancer (except treated basal cell or squamous cell carcinoma of the skin) 13. have a history of clinically significant allergic reactions; 14. have used any psychotropic drug in the past month, except individuals who are on a stable dose of a Selective Serotonin Reuptake Inhibitor for at least two months; 15. intend to donate blood or blood products during the treatment phase of the study; 16. have a Body Mass Index (calculated as weight in kilograms divided by the square of height in meters) less than 15 or greater than 28 or weight less than 45 kg.