N acetylcysteine in the treatment of alcohol use disorder: a randomized, double-blind, placebo-controlled trial

N-acetyl cysteine (NAC) is a potent antioxidant that modulates glutamatergic signalling which is thought to play a role in alcohol use disorder (AUD). There have been no clinical trials investigating NAC for AUD. We aimed to conduct a 28 day double-blind, placebo-controlled (PL) randomized trial of NAC in the treatment of AUD (NCT03879759). A total of 42 participants with AUD (56% alcohol-related liver disease) were randomized to receive placebo or NAC 2400 mg/day. Feasibility outcomes included treatment retention and adverse events. Primary clinical outcomes included alcohol consumption (heavy drinking days, standard drinks per drinking day). Secondary clinical outcome measures included craving, liver tests, and psychological outcomes. There were no significant differences in overall retention between treatment groups (χ2(1) = 0.14, P = 0.71: 86% vs 76% for placebo and NAC, respectively). The most commonly reported adverse event in NAC-treated individuals included headache (14%). For standard drinks per drinking day, there was a significant overall effect of time (F = 9.18, P < 0.001), no significant effect of treatment (F = 0.75, P = 0.79), and a significant time x treatment (NAC vs PL) effect (F = 2.73, P < 0.05). For number of heavy drinks per day, there was a significant overall effect of time (F = 3.16, P < 0.05) but no significant effect of treatment or time x treatment (P = 0.17). There were no significant NAC vs PL effects on secondary clinical outcome measures. In the first trial of NAC for the management of AUD, NAC appears to be feasible and safe. Although there was a significant effect of NAC vs placebo on some alcohol measures such as drinks per drinking day, there does appear to be a variable pattern of effect across time suggesting that a larger trial incorporating a longer treatment duration is now required to determine efficacy.