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"Chart C" (Posted on PARKINSN list Jan 1997)
Click here to see the chart mentioned by Brian Collins, in his post titled Sinemet and the Analysis program posted to the PARKINSN list. Some notes to go with it are here.....
- CHART C - SHOWING PRIMARY AND OVERDRIVE AREAS OF OPERATION
----------------------------------------------------------
2) The three bell-shaped lines in black represent three tablets, taken at the optimum time so that the combined effect is linear, and produces stable operation in the yellow 'Primary target area. When I first ran the program to see if my predictions were correct, the result was almost as good as that, apart from the local effect of meals.
3) Although it was not necessary to pursue the effects beyond the +1 level, I inevitably at times strayed into the +2 area (by accidentally taking too much Sinemet), and back in 1994 I wrote:" The computer model appears to simulate my subjective reaction to levodopa over the mid to low dose range (+1 to -2, but not over the high dose +1 to +2 ramge. The time duration of an overdose condition seems to be out of all proportion to the levodopa quantity." At that time, I simply marked it down as oneof life's little mysteries and carried on.
4) When I joined the Parkinsn list, I was amazed to see that several people were deliberately driving themselves into the yellow blob which I have called the overdrive region, by taking large doses of Sinemet in the early morning, and then coasting along with a few boosters during the day. (See the red line.)The strange thing about operating in the overdrive zone is that it takes less sinemet to get into, and stay in the overdrive region than it takes to operate in the Primary target.
5) The people operating in this area seem to agree that although many PD symotoms remain, they are milder and can be tolerated. In the interests of furthering the cause of science, I tried driving myself up the red line, by taking an extra Sinemet 100/25 when I got up in the morning. I had no trouble getting into the overdrive region, and found that for me, the level of dyskinesia was totally unacceptable, and did terrible things to my collapsed vertebrae. Maybe it varies for different people, or maybe they just grit their teeth and carry on, but I couldn't live like that.
6) The people who use this method of operation agree on one key fact: At the end of the day, these high-flyers have got to come down to the ground. As the subjects descend through the no-mans zone around condition =1 , they have to run the gauntlet of really strong dykinesias - there is apparently no escaping it.
- I wonder if this is your diphasic dyskinesia, David ?
Another entirely unrelated possibility occurs to me, concerning the protective properties of Carbidopa, whose job is to protect the levodopa as it travels from the small intestine to the brain. We know that only a fraction of the original intake survives the trip, but it appears to me that during the cycle of a single tablet, the Carbidopa could go through phases in which it was more or less successful at its job. Thus we could find that as the end of the cycle for that tablet, the Carbidopa finally bludgeons the opposition into submission, thus allowing a strong dose of Sinemet through at the end.
Regards
--
Brian Collins <bjc@globalnet.co.uk>
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