I copied and pasted the following from the NSDA website, FAQ page:"Oral medications provide little relief in the symptoms of spasmodic dysphonia, but if other forms of dystonia are present, medications may help relieve those related symptoms. There are several possible categories of medications used in the treatment of dystonia including anticholinergics, benzodiazepines, and baclofen. The treatment of spasmodic dysphonia must be tailored to the individual patient."
I have ABSD with voice tremor and tried Inderal which sometimes is effective in the treatment of tremor. It didn't help me, but my cousin who has ADSD with tremor felt it helped her.