Future directions in the treatment of Parkinson's disease.

The development of treatment for the symptoms of Parkinson's disease (PD) has been one of the most notable successes of neurology. Dopaminergic therapies in the form of levodopa, dopamine agonists, or monoamine oxidase B inhibitors significantly improve the characteristic motor symptoms of bradykinesia and rigidity, with a beneficial effect upon tremor in a proportion of patients. Novel delivery of dopaminergic drugs whether in the form of once a day sustained release preparations or transdermal applications ensures that they remain at the forefront of PD treatment. The development of drugs to slow the progression of PD has attracted considerable attention and there appears to be some measure of success although additional studies need to be performed. A range of nondopaminergic drugs including alpha 2-adrenergic antagonists, serotoninergics, and adenosine A2a antagonists are in late-stage development for PD and offer benefit for motor symptoms and motor complications.