Dear Ms Dalby: I can hardly appreciate the pain you and your mother have had because of the toxic efects of Risperidone (Risperdal). You will have to keep close watch on your mother's physicians; that they must not give her this drug. The fact that she is not responding to Sinemet is no excuse to mindlessly substitute another toxic antiparkinson agent.Risperidone is one of the most toxic of antiPD agents. It produces deep sedation, extrapyramidal efects (that may be irreversible) and hypotension. I know what this is like , when a few months ago I had one day's treatment with Risperidone. It turned me into a zombie, made me stiff as a board, so that I could not get out of bed, for which low blood pressure was also responsible. I'm sorry not to report anything that might be positive; I can only give you my sympathy. Steven Mayer [[log in to unmask] Steven E. Mayer, Ph.D.