Anticholinergic withdrawal and benzhexol treatment in Parkinson's disease.

The effects of slow withdrawal of anticholinergic medication and addition of benzhexol (8 mg/day) have been studied in patients with Parkinson's disease on stable levodopa therapy. Withdrawal of anticholinergic drugs led to measurable and often severe deterioration in about two-thirds of patients. Addition of benzhexol produced a slight but definite additional improvement in those patients in whom anticholinergics were withdrawn before the trial. Anticholinergic drugs thus still have a part to play in the treatment of Parkinson's disease, for they produce benefit in addition to that provided by levodopa.