N-acetylcysteine as an adjunctive treatment for smoking cessation: a randomized clinical trial

Objective: This randomized controlled trial examined the efficacy and safety of N-acetylcysteine as an adjunctive treatment for smoking cessation. Methods: Heavy smokers were recruited from smoking cessation treatment for this 12- week randomized controlled trial. Eligible tobacco use disorder outpatients (n=34) were randomized to N-acetylcysteine or placebo plus first-line treatment. Abstinence was verified by exhaled carbon monoxide (COexh). The assessment scales included the Fagerstrom Test for Nicotine Dependence, the Hamilton Depression Rating Scale, the Hamilton Anxiety Rating Scale, the Minnesota Nicotine Withdrawal Scale, and the Medication Adherence Rating Scale. We also assessed anthropometrics, blood pressure, lipid profile, and soluble tumor necrosis factor receptor (sTNF-R) levels 1 and 2. Results: First-line treatment for smoking cessation plus adjunctive N-acetylcysteine or placebo significantly reduced COexh (p < 0.01). In the N-acetylcysteine group, no significant changes were found in nicotine withdrawal symptoms, depressive and anxiety symptoms, anthropometric measures, blood pressure, or glucose compared to placebo. However, there was a significant reduction in sTNF-R2 levels between baseline and week 12 in the N-acetylcysteine group. Conclusions: These findings highlight the need to associate N-acetylcysteine with first-line treatment for smoking cessation, since combined treatment may affect inflammation and metabolism components.