I've tryed Xanax before and it was the only thing which improved it significantly, though I was to afraid to take it regularly due to the high risk of developing a dependence on the drug because I know that especially benzos can really lead to some bad consequences. Experimenting with different types of substances is actually tempting at first but when it comes down to treating it, I would strongly advise anyone who suffers from stuttering to avoid drugs as a coping mechanism.