N-acetylcysteine for Tobacco Use Disorder

Inclusion Criteria: 1. Age 18-65 2. Daily smoker for ≥6 months, smoking approximately ≥5 cigarettes per day on average in the past month or must meet the criteria for nicotine dependence 3. Be interested in quitting smoking (defined as a 2 or above on a 10-point Likert scale assessing readiness and interest in quitting (1=not at all ready/interested, 10=extremely ready/interested) 4. Willing to engage in a 3-day quit attempt as part of study procedures 5. Willing to abstain from cannabis use during study procedures (since inhaled cannabis will affect breath carbon monoxide readings). 6. If female, agreement to use birth control (any form) to avoid pregnancy during study procedures Exclusion Criteria: 1. Any serious or unstable medical/psychiatric disorder (including severe substance use disorders, other than tobacco use disorder) in the past month that may interfere with study performance based on PI judgment 2. Current pregnancy or breastfeeding 3. Current use of medications with smoking cessation efficacy 4. Known hypersensitivity to NAC 5. Use of carbamazepine or nitroglycerin (or any other medication deemed to be hazardous if taken with NAC) within 14 days of study participation