I recall reading that RLSmi has taken DXM since his dx and seems to have had a relatively slow progression. If he reads this and would elaborate on effect & dosage, I would be appreciative. Has anyone else had experience with DXM? Sounds promising enough for a clinical trial...

http://www.hindawi.com/journals/mi/2012/401264/
Volume 2012 (2012)

Oxidative Stress and Microglial Cells in Parkinson's Disease

Morphinan-Based Anti-Inflammatory TherapeuticsSeveral studies using PD animal models or in vitro cell cultures have shown that the morphinan compound dextromethorphan (DM) and its metabolites are neuroprotective due to their anti-inflammatory properties and inhibitory function towards microglia activation [59, 109, 110].

DM inhibits microglia activation and is neuroprotective when administered daily to mice that had been injected with MPTP [109].

Another metabolite of DM, 3-hydroxymorphinan (3-HM) was shown to have the greatest potency (of several tested methorphanins) for attenuating the loss of DA neurons in the SN, as well as restoring motor functions in the same MPTP-mouse model of PD

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3255316/

The Neuroprotective Disease-Modifying Potential of Psychotropics in Parkinson's Disease

Results indicate that, from a PD pathobiology perspective, the safest drugs (i.e., drugs least likely to promote cellular neurodegenerative mechanisms balanced against their likelihood of promoting neuroprotective mechanisms) include pramipexole, valproate, lithium, desipramine, escitalopram, and dextromethorphan. Fluoxetine favorably affects transcription of multiple genes (e.g., MAPT, GBA, CCDC62, HIP1R), although it and desipramine reduced MPTP mouse survival. Haloperidol is best avoided.

In MPTP mice, dextromethorphan protected dopamine neurons [87, 88], dopamine concentrations [87], and locomotor activity [87] and reduced glutamatergic excitotoxicity on dopamine neurons [89]. A previous study had not demonstrated protection of dopamine concentrations in this model [89]. Dextromethorphan also protected dopamine concentrations in mice treated with both MPTP and diethyldithiocarbamate [89]. In the methamphetamine mouse model of PD, dextromethorphan protected dopamine neurons and prevented microglial activation [90]. Finally, in the mouse neuroinflammatory LPS model of PD, dextromethorphan protected dopamine neurons, dopamine concentrations, and locomotor activity [87].

Drugs with multiple actions that may confer disease-modifying neuroprotection include dextromethorphan, valproate, lithium, and pramipexole. These drugs have neuroprotective effects on αSyn, except that the HDACI dextromethorphan lacked direct data for this protein, and lithium had neuroprotective effects on both αSyn and tau protein. One potential therapeutic strategy that might be tested in animal models and humans is the combination of valproate with dextromethorphan in attempting to therapeutically modulate H3 HDAC, GSK-3, αSyn, ROS, apoptosis, and trophic factors.