N-acetylcysteine for therapy-resistant tobacco use disorder: a pilot study

Introduction: N-Acetylcysteine (NAC) may have efficacy in treating tobacco use disorder (TUD) by reducing craving and smoking reward. This study examines whether treatment with NAC may have a clinical efficacy in the treatment of TUD. Methods: A 12-week double blind randomized controlled trial was conducted to compare the clinical efficacy of NAC 3 g/day versus placebo. We recruited 34 outpatients with therapy resistant TUD concurrently treated with smoking-focused group behavioral therapy. Participants had assessments of daily cigarette use (primary outcome), exhaled carbon monoxide (COEXH) (secondary outcome), and quit rates as defined by COEXH<6 ppm. Depression was measured with the Hamilton Depression Rating Scale (HDRS). Data were analyzed using conventional and modified intention-to-treat endpoint analyses. Results: NAC treatment significantly reduced the daily number of cigarettes used (Delta mean +/- SD = -10.9 +/- 7.9 in the NAC-treated versus -3.2 +/- 6.1 in the placebo group) and COEXH (Delta mean +/- SD = -10.4 +/- 8.6 ppm in the NAC-treated versus -1.5 +/- 4.5 ppm in the placebo group); 47.1% of those treated with NAC versus 21.4% of placebo-treated patients were able to quit smoking as defined by COEXH<6 ppm. NAC treatment significantly reduced the HDRS score in patients with tobacco use disorder. Conclusions: These data show that treatment with NAC may have a clinical efficacy in TUD. NAC combined with appropriate psychotherapy appears to be an efficient treatment option for TUD.