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Book Excerpt: Dementia with Lewy Bodies & Parkinson’s Disease Dementia

Dr. Ahlskong on DLB and Parkinson'sIf diagnosed with dementia with Lewy bodies (DLB) or Parkinson’s disease, one would naturally want to do everything possible to halt or at least slow down the disease progression. Are there medications for this purpose? Unfortunately, no controlled trials have analyzed this question among people with DLB. On the other hand, multiple randomized clinical trials have assessed a variety of drugs as possible agents to slow the progression of Parkinson’s disease that could be relevant to all Lewy conditions.

Major clinical trials assessing drugs to slow the progression of Parkinson’s disease date back to the 1980s. In each of these trials hundreds of Parkinson’s disease patients from multiple participating medical centers were enrolled and randomized to either the study drug or placebo. Drugs that have been investigated included higher doses of vitamin E; the monoamine oxidase B (MAO-B) inhibitor selegiline (deprenyl); the dopamine agonists pramipexole and ropinirole; as well as two experimental agents shown in animals to reduce apoptosis (a cell death process that might be relevant to neurodegeneration). Unfortunately, none of these large trials provided compelling evidence for slowing the progression of Parkinson’s disease. These studies’ results were either negative or so confounded and inconclusive that a meaningful interpretation could not be drawn.

Most recently, the newer MAO-B inhibitor rasagiline (which also reduces apoptosis) was similarly assessed in two large clinical trials. The outcomes from these rasagiline studies were mixed and difficult to interpret. A U.S. Food and Drug Administration (FDA) Advisory Panel concluded that there was insufficient evidence to conclude that rasagiline has disease-slowing properties. What confounded these outcomes (as well as some of the earlier trials) was that the study drug also had symptomatic benefits (i.e., treated Parkinson’s disease symptoms). Since the outcome measures were clinical assessments of parkinsonism, it was difficult to distinguish symptomatic benefit from slowed disease progression.

Other drugs that have been studied as potential agents to slow the progression of Parkinson’s disease include creatine (used by muscle builders) and the antibiotic minocycline. To date, no proof has been produced showing that these or any other agents truly have a disease-slowing benefit.

 

Reprinted from Dementia with Lewy Bodies and Parkinson's Disease Dementia: Patient, Family, and Clinician Working Together for Better Outcomes by Dr. J. Eric Ahlskog, MD PhD with permission from Oxford University Press, Inc.  Copyright © Oxford University Press 2014.