Hi, there is an FDA drug being used by many people with MS but a few with PD, myself included. It is low dose naltrexone, LDN, I have been taking it now for 28 months along with low doses of Sinemet and Mirapex. I was able to cut back on my Sinemet by 2/3rds to 1x 25/100. My problem was tremor. It's gone for now, I don't think I've progressed. LDN is supposed to stop the progression of many diseases. There are research papers that seem to support the claims made by the developer of LDN, Dr. Bernard Bihari.
http://www.lowdosenaltrexone.org/index.htm
Ashley

From a NIH paper, naloxone and naltrexone are similar.
"The purpose of this study was to identify two neuroprotective compounds with a similar bimodal dose response, to discern whether the neuroprotective characteristics of each compound could converge into a single mechanism, and through this process, to elucidate a common femtomolar site of action.

Parkinson’s disease (PD) is characterized by the specific and progressive death of dopaminergic neurons in the substantia nigra (SN); other neuronal cell types are much less affected. Recent reports have linked inflammation to neurodegenerative disease, where microglia, cells of myeloid lineage responsible for innate immunity in the brain, are considered to be the major cell type underlying the inflammation-mediated neurotoxicity (7 8 9) . The activation of microglia is a complex process involving the release of several soluble proinflammatory factors [tumor necrosis factor {alpha} (TNF-{alpha}), PGE2, IL-1] and free radicals (nitric oxide, superoxide) (7) . Current replacement therapy with L-dopa is able to alleviate disease symptoms, but is unable to alter the disease course. Thus, therapeutic interventions designed to inhibit the microglial inflammatory response offer hope for attenuation of the neurodegenerative disease process. The current anti-inflammatory treatments available, including steroids and nonsteroidal anti-inflammatory drugs, are limited by the ability to influence only a small portion of the microglial response (10) . Thus, identification of compounds acting on novel targets to inhibit the release of a wide range of proinflammatory factors from overactivated microglia is of paramount importance. In the ensuing study, we report that femtomolar concentrations of naloxone and the peptide fragment glycine-glycine-phenylalanine (GGF) attenuate a broad spectrum of the microglia inflammatory response (reactive oxygen species (ROS) and proinflammatory factors) and are neuroprotective with extremely potent efficacy through the inhibition of microglial NADPH oxidase."

http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract