Maybe I just have a slowly progressing case, but I seem to be doing extremely well for having been diagnosed in April of 2001. I continue to take 4mg of dextromethorphan HBr in the form of over the counter pediatric cough syrup. I began taking DM in 2003 on the strength of the work of Dr. J-S Hong's laboratory at the National Institues of Environmental Health at Research Triangle NC. He demonstrated that ultra-low (femtomolar) concentrations of the morphinan drugs naltrexone, naloxone, and dextromethorphan were equally effective in preventing activation of microglial cells in cell cultures of mouse midbrain by lipopolysaccharide, a bacterial component which has been shown to be a possible trigger of neurodegeneration.
I base my dosage and method of DM use on that found effective with Low-Dose naltrexone by those taking it for a variety of conditions such as MS, fibromyalgia and Crohn's disease. I am simply using the form of this class of drugs that is available over the counter.
Of course, I also contine to take carbidopa/levodopa CR, 150/600 mg each day, along with 100mg amantadine, 900mg CoQ10, gonzo multivitamins and minerals, a tonic with very high resveratrol content, Welbutrin and Cymbalta.

We recently returned from a 5000-plus mile driving trip from Louisiana to Seattle via Yellowstone NP. The wife and I were returning our grandson home after spending the summer with us. The only downside of PD I experienced was the "epic" tumble I took (witnessed by the 16 year old grandson) when I attempted to make my way down the riverbank to an especially beautiful stretch of rapids on the Yellowstone river. Nothing broken except for cuts, scratches and bruises, along with my dignity. Highly skilled roadside first aid (and consolation, along with admonitions to avoid such foolhardy expeditions in the future) administered by my DW and aforementioned grandson soon had the bleeding stanched and all of us proceeding with sightseeing.

That last part really had nothing much to do with my dextromethorphan use, (except perhaps as a testimony to its possible salutory effects on bone strength in a 71 year old parkie) but it has been so long since I posted that I just had to slip it in!

Robert