Combining Varenicline and Naltrexone for Smoking Cessation

Inclusion Criteria: 1. Be treatment-seeking for smoking cessation and have a desire to reduce or quit drinking 2. Be between the ages of 21 and 65 3. Be able to provide informed consent 4. Smoke 5 or more cigarettes per day for the past year 5. Currently drink heavily according to the National Institute on Alcohol Abuse and Alcoholism (NIAAA) guidelines: for men, \> 14 drinks per week or ≥ 5 drinks per occasion at least once per month over the past 12 months; for women, \> 7 drinks per week or ≥ 4 drinks per occasion at least once per month over the past 12 months 6. Pass the physical exam and associated laboratory tests, as determined by study physician Exclusion Criteria: 1. Have clinically significant alcohol withdrawal, indicated by a score ≥ 10 on the Clinical Institute Withdrawal Assessment for Alcohol (CIWA-Ar) and assessed at the in-person screening visits 2. Have lifetime DSM-V diagnosis of schizophrenia, bipolar disorder, a psychotic disorder, or any other psychiatric disorder as determined by the clinical interview 3. Have major depressive disorder within the past year requiring treatment as determined by the clinical interview using DSM-V criteria 4. Have a current or lifetime DSM-V diagnosis of a substance use disorder, other than for alcohol or nicotine, as determined by the clinical interview 5. Have a prior history of taking FDA approved medications (i.e. varenicline or bupropion) for smoking cessation 6. Be currently using any forms of nicotine replacement therapy (past use is acceptable) 7. Be currently using tobacco products other than cigarettes (such as e-cigarettes, cigars, or chewing tobacco) 8. Have a serious medical illness (significant cardiovascular disease; uncontrolled hypertension; hepatic or renal disease) that would contraindicate participation, as determined by the study physician 9. Be currently taking insulin or oral hypoglycemic medication 10. Be currently taking opioid pain medications or any form of opioid agonist maintenance therapy (such as methadone or buprenorphine) 11. Be currently taking any other psychoactive medications; such as anti-depressants, mood stabilizers, anti-seizure medications, sedatives-hypnotics, anxiolytics, stimulants or antipsychotics 12. Have self-reported use of cocaine, methamphetamine, heroin or other illicit drugs in the previous 60 days, verified by urine toxicology screen 13. For women, must not be pregnant (as indicated by self-report or a positive pregnancy test at any study visit), nursing, or planning to become pregnant while taking part in the study, and must agree to a reliable method of birth control