Managing the patient with newly diagnosed Parkinson disease.

The treatment of early Parkinson disease (PD) is generally symptomatic, although therapy that also offers neuroprotection in early-stage PD would be welcomed. Levodopa remains the most effective agent for relief of PD symptoms, but chronic levodopa therapy is associated with motor fluctuations and dyskinesias, and clinicians may therefore opt to postpone its use. Alternatives to levodopa in early PD include monoamine oxidase (MAO)-B inhibitors, amantadine, and dopamine agonists. MAO-B inhibitors have only mild symptomatic effects. Amantadine is associated with improvement in functional disability and, in a subset of PD patients, a robust symptomatic improvement. Dopamine agonists improve symptoms and may have a neuroprotective effect. Partial dopamine agonists, adenosine A(2A)-receptor antagonists, and safinamide are symptomatic therapies that are under investigation. Neuro protective strategies under study include enhancement of mitochondrial function, antiinflammatory mechanisms, calcium channel blockade, and uric acid elevation. Deep brain stimulation may slow cognitive and motor decline when used in early PD. Stem cell therapy and gene therapy are still under investigation.