Dear Bob: Was your inquiry pertaining to a new tremor med. or about older tried and true ones? My husband has been using Cogentin since the day he was diag. for his early tremor and still uses l mg. / day or the tremor comes back..... has been dealing with PD almost l3 yr. now.... If your on the search for a newer model med, I'll be watching with you .... Best wishes....... Marie carepartner husband 69/l2