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Numerous postings include something like the folowing: <<The docs have me on Wellbutrin for the "lability" and eldepryl for now. I'm at the point where I could use some PD relief so we a trying the standard arsenal of meds - before starting on Sinemet. ... Rick Barrett ([log in to unmask])>>> I continue to be puzzled by the reticence to use the chemical that the body normally uses! levo-DOPA is the normal metabolic chemical that is metabolized by the body as the pre-cursor for metabolizing dopamine. It is the natural chemical that is perhaps least likely to be toxic. The philosophy of using least amount required is not emphasized by many doctors. This seems imprudent to me. The known peaking rapidly - then decaying rapidly - concentration of levodopa in the bloodstream - characteristic of carbidopa/levodopa medication means that the regular medication should be taken every two to three hours - because the half-life is about two hours. If half of a 25/100 carbi/levo-dopa tablet is sufficient to reduce the symptoms to tolerable level, then that dosage is sufficient for that patient at that time. Actually, the CR version is more convenient - and less affected by digestive variations which affect amount of levodopa getting into the bloodstream - because halves of the 25/100 Sinemet CR medicate for the usual 4 to 5 hours between meals (without peaks). If the beginning medication is three half-25/100 Sinemet CR tablets per day at awakening, lunch, and evening meal, the dosage is level in blood concentration for the hours awake. (this near constant supply of supplemental levodopa can be approximated by taking six halves <or twelve quarters> of carbidopa/levodopa medication at equal time intervals through the day - to save money.) The possibility exists that carbidopa by itself might raise the concentration of natural levodopa that exists in the patient newly diagnosed with mild symptoms. The conjecture that l-deprenyl keeps the metabolism of dopamine from occurring - thereby increasing the level of dopamine in the brain - is cited as the reason that Eldepryl reduces symptoms. This prompts me to ask whether this selegiline hydrochloride functions in like manner throughout the body where dopamine is part of the normal bio-chemicals. Does anyone know of any data relevant to the two conjectures of carbidopa-alone or l-deprenyl-alone? Do measurements of levodopa in bloodstream exist for normal persons? Same given carbidopa-alone, Eldepryl-alone, placebo(?)? Is carbidopa detrimental above some dosage? Eldepryl is potentially toxic if SSRI effect inhibits type A instead of only type B if I recall the logic for limiting to 10 mg. per day. Is carbidopa at high dosage entering the brain and retarding conversion of levodopa to dopamine? Have we sacrificed a few small creatures to determine this? I would like to know. Does the blood absorption level of levodopa have the effect of limiting how much levodopa can be absorbed from the intestine? (In other words, does the patient taking very large amounts get more into the bloodstream?) Also, does the amount of carbidopa taken with it change this maximum levodopa concentration in blood? This might tell those taking 50/200 Sinemet CR medication every two hours that they are not absorbing much of it. We are told 69% of the levodopa concentration provided by the regular Sinemet is typical of the CR tablet. Does this percentage remain constant no matter how many are taken? Not likely - IMNSHO. (id est, not likely in my not so humble opinion.) ron 1936, dz PD 1984 Ridgecrest, California Ronald F. Vetter <[log in to unmask]> http://www.ridgecrest.ca.us/~rfvetter/