Tetrodotoxin alleviates acute heroin withdrawal syndrome: a multicentre, randomized, double-blind, placebo-controlled study.

1. Tetrodotoxin (TTX) is a powerful sodium channel blocker extracted from the puffer fish. The efficacy and safety of TTX as monotherapy for the treatment of acute heroin withdrawal syndrome were evaluated in the present study. This 7-day, multicentre, randomized, double-blind, placebo-controlled study was carried out between December 2008 and October 2009. In total, 216 patients who met the Diagnostic and Statistical Manual of Mental Disorders IV diagnosis of heroin addiction were recruited. After providing written informed consent, subjects were randomly assigned to double-blind treatment in one of the following groups: 5 μg TTX group (group 1), 10 μg TTX group (group 2) or the placebo group (group 3). 2. Evidence suggests that both 5 and 10 μg TTX significantly reduced withdrawal symptoms by day 3 compared with placebo, and there was no significant difference in the incidence of adverse events in the three groups. 3. In conclusion, this clinical trial shows that TTX (5 and 10 μg given t.i.d.) is effective in alleviating opiate withdrawal symptoms with few side-effects.