Neuroprotective therapy for Parkinson disease
- Daniel Tarsy, MD
Daniel Tarsy, MD
- Professor of Neurology
- Harvard Medical School
The pharmacologic treatment of Parkinson disease (PD) can be divided into neuroprotective and symptomatic therapy. In practice, however, nearly all of the available treatments are symptomatic in nature and do not appear to slow or reverse the natural course of the disease.
This topic will review potential neuroprotective therapies for PD. Other aspects of PD are discussed separately. (See "Etiology and pathogenesis of Parkinson disease" and "Clinical manifestations of Parkinson disease" and "Diagnosis and differential diagnosis of Parkinson disease" and "Pharmacologic treatment of Parkinson disease".)
Neuroprotective therapy of PD is still theoretical, but it is based on the concept that the three to four hundred thousand at-risk dopaminergic neurons in the human substantia nigra can somehow be protected from the complex degenerative process that causes premature cell death and depletion of dopamine. Once identified and shown to be effective, neuroprotective drugs could be used in patients with early clinical signs of disease or potentially even prior to the appearance of disease in those shown to be at genetic risk. Several potential neuroprotective agents for PD have shown some promise in animals and/or humans, including selegiline and rasagiline (both monoamine oxidase inhibitors), and the natural substance coenzyme Q10. However, no treatment to date has proven to be effective for neuroprotection in PD.
Our suggested approach for patients with newly diagnosed PD is to make them aware that most of the current therapeutic research in PD involves a search for neuroprotective agents ; this gives them hope. To date, however, only weak signals have emerged for a few agents.
Accumulating clinical trial data suggest that levodopa either slows the progression of PD or has a prolonged benefit even after the drug has been stopped. These data are presented separately. (See "Pharmacologic treatment of Parkinson disease", section on 'Levodopa'.)
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