N-acetylcysteine in the treatment of craving in substance use disorders: Systematic review and meta-analysis

BACKGROUND AND OBJECTIVES: Recent neurobiological evidences along with clinical observations justify the use of N-acetylcysteine (NAC) as a medication for craving. The objective of our study was to assess the evidence of efficacy of NAC for craving in substance use disorders in randomized clinical trials (RCTs). METHODS: Systematic review of the RCTs literature (PROSPERO number 56698) until February, 2017, using MEDLINE, Cochrane Library and clinicaltrials.gov. We included seven RCTs (n = 245); most with small-to-moderate sample sizes. The main outcome was the Hedges' g for continuous scores in a random-effects model. Heterogeneity was evaluated with the I2 and the χ2 test. Publication bias was evaluated using the Begg's funnel plot and the Egger's test. Meta-regression was performed using the random-effects model. RESULTS: Comparing NAC versus placebo, NAC was significantly superior for craving symptoms (Hedges' g = 0.94; 95%CI 0.55-1.33). The funnel plot showed the risk of publication bias was low and between-study heterogeneity was not significant (I2  = 44.4%, p = 0.07 for the χ2 test). A subgroup analysis performed using meta-regression showed no particular influence. DISCUSSION AND CONCLUSIONS: NAC was superior to placebo for craving reduction in SUDs. The relatively small number of trials and their heterogeneous methodology were possible limitations; however, these positive thrilling results stimulate further studies for clarifying the potential impact of NAC for craving symptoms in SUDs. SCIENTIFIC SIGNIFICANCE: The safety profile of NAC and favorable tolerability, in addition to being an over-the-counter medication, presents with an interesting potential clinical use for craving in SUDs. SCIENTIFIC SIGNIFICANCE: The safety profile of NAC and its favorable tolerability, in addition to being anover-the-counter medication, presents with an interesting potential clinical use for craving in SUDs. (Am J Addict 2017;26:660-666).