There are some personal communications (medical knowledge) that advocate the use of two to three conservative treatment modalities at the same time. For example adding anticholinergic drugs to the liquid that is used with the iontophoresis machine (Drionic). Another example is taking anticholinergic agents at the same time that Drysol is applied to the hands. All of these combination modalities were done in a very small number of cases without any control studies. This particular fact makes it very difficult to draw a definite conclusion with regard to the validity of these treatment options.
Since there are no real clinical studies with follow-up performed it leaves this combination option to be tried by the treating doctor and the patient. It is a time consuming process but never the less could be tried.