Soy isoflavones for the treatment of cocaine use disorder: an open-label pilot study

Soybeans contain different isoflavones (mainly daidzein) which work as reversible inhibitors of aldehyde-dehydrogenase-2 enzyme (ALDH2). This activity has been related in animal experiments with a reduction of cocaine use. Our aim was to carry out an open-label pilot study to evaluate the possible efficacy of soy isoflavones as natural inhibitor of ALDH2 in cocaine use disorder. Nine subjects with severe cocaine use disorder participated in a single-center, open, non-controlled trial during 12 weeks of treatment and 4 of follow-up. The Substance Use Report (SUR) showed that three subjects (33.3%) reported a cocaine consumption of less than 20% (80% non-use days) from 10 to 12 weeks of the treatment period, from two (22.2%) at baseline, although non-significant. A finding that could not be confirmed by the detection of urine metabolites of cocaine. Seven participants (77.8%) completed the study at 16 weeks and one (1.11%) at 12 weeks. Urine concentrations of isoflavones, demonstrated that eight participants (88.9%) followed the treatment along the study. The Severity Dependence Scale (SDS) score showed a significant decrease between baseline to 12 weeks, baseline to 16 weeks and 12 to 16 weeks; the Brief Substance Craving Scale (BSCS) and Cocaine Selective Severity Assessment (CSSA) decreased their values but not significantly. Significant improvements in different areas of the SF-36 scale were observed: body pain scores decreased from baseline to 16 weeks statistically significant; social function improved its scores from baseline to 12 weeks and from baseline to 16 weeks significantly; the rest of areas increased their scores but not significantly. These findings show lower ratios of cocaine use days, and high retention and adherence to treatment although the acquisition of complete abstinence was not observed. Soy isoflavones could be considered a potential treatment in future research, to be confirmed by placebo-controlled studies with adequate sample size.