That is true, there are no fda approved medications. However, that's a different argument. Your argument is that there are no effective medications. That's disingenuous and incorrect. Indeed, there's nothing stopping somebody with a stutter to see a psychiatrist and ask for a prescription of a D2 receptor antagonist to see if it works for them, the caveat is that there are side effects involved. I'll also add that some benefit, while some don't, this is because dopamine antagonism is only a part of a greater whole.