N-acetylcysteine improves microcirculatory flow during smoking: New effects of an old drug with possible benefits for smokers

Background: Cigarette smoking provokes marked acute changes in the microcir culatory vasculature, including a reduced blood flow velocity. In accordanc e with the hypothesis that the reduced blood flow is due to an imbalance be tween pro-oxidants and oxidants, we recently showed that most of the reduct ion could be reversed by a high dose of vitamin C. Hypothesis: In the present work we tested the hypothesis that N-acetylcyste ine, a mucolyticum and an antioxidant, may have an effect on the smoking-in duced changes observed by vital capillary microscopy of the nailfold. Methods: In all, 37 healthy volunteers of both genders and with varied smok ing habits were treated with N-acetylcysteine 200 mg t.i.d. for 2 weeks. In vivo investigation of the microcirculation by capillaroscopy was performed before and after treatment. Results: Treatment with N-acetylcysteine significantly reduced the smoking- induced relative decrease in capillary blood flow velocity in a group of vo lunteers with varied smoking habits (p = 0.0016). The preventive effect was clearly significant in smokers (p = 0.003). Conclusion: Treatment with N-acetylcysteine has a positive impact on microc irculatory flow during smoking, particularly in habitual smokers.