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Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Brian Collins <[log in to unmask]> wrote: <<<On Sat 30 Nov, Joao Paulo Carvalho wrote: > Brian Collins wrote: > Brian it may be just a false feeling but seems to me that when I take > levedopa and go to play soccer early in the morning the effect of it is > a better ? absorption of the drug.This is one thing that has aroused > suspection to me anyway. clip Hello Joao Paulo, nice to hear from you again. You raise a good point: The fact that you are running and expending a lot of energy will certainly cause an increase in the rate of flow of blood around the body. The levodopa will thus be transportd to the brain more quickly, so that the apparrent effect will be like a bigger tablet, but one with a reduced effective duration. At a guess, I would suspect that the size of the effect would be related to the pulse rate. So, our athlete is going to get a boost of levodopa with a reduced time duration. Since most PWP who engage in highly energetic activities tend to be those who are in the early stage of the disease, they are unlikely to notice the overdose effect.( As illustrated in my chart which was discussed a few weeks ago), so we are left with the reduced duration. - Perhaps the sportsman should just increase the rate of tablets, rather than the size of dose.>>>> Joao and Brian, I believe the absorption is rapid once the levodopa is dissolved - and - gets into the small intestine from whence it can be 'oozed' into the bloodstream. There is some likelihood that the peak concentration is higher due to exercise. Yes, there could be faster arrival at the brain. If both, the transport across the blood-brain-barrier should be higher and quicker. Most importantly IMO (and Brian's apparently) - is the knowledge that the typical concentration in the blood reduces rapidly. If the person taking the medication needs a level of 50% of the peak concentration to have enough levodopa cross the barrier into the brain, that person will need more medication after about 1.0 hour. The 'overdose' effect may depend on some of the blood characteristics at the barrier: pressure pulsation range, rate, consistency, pH, temperature, et cetera - and the transport into the brain may be limited by some still-healthy-normal natural levodopa limiter in the brain. The wasting of medicine by having more concentration than optimum - and the minimization of 'overdose effect' for those who have a 'narrow window' of acceptable (optimum) dosage rate (= concentration level) are both best handled by taking half the dose twice as often! The flow rate limiting is better done by a modified insulin pump putting the levodopa into the lower intestine (as Alan Bonander had) or into the blood stream directly; but, the flow-rate-control using pills is better with halves twice, better (if we do not count the added effort and nusiance factor (Alan had to make the solution and clean the pump, etc) and the continuing dosing) to take one-third three times, one-quarter four times, et cet.. You are not convinced that flow rate is controlled by the ingestion rate, Brian. But, note that that is exactly what "increasing the rate of tablets" as you put it in your last sentence predicates. The size of the dose (above the concentration needed) is wasted medicine (and may be detrimental in some way - as is the extra carbidopa) - therefore, the last part of your last sentence should carry this advice to reduce the amount taken to that which provides the needed concentration - until the next pill must be taken. Id est, ingesting frequency increase is the primary control with current medications. (The entacapone and tolcapone are to inhibit the COMT metabolism which will change this decay rate situation. The transdermal patch of dopamine agonist of longer duration may become available and be near the metering pump excellence of control - perhaps even better since food does not interfere!) Brian, you can delete the "perhaps" from your last sentence - after you have agreed with these arguments. tafn, ron -- ron 1936, dz PD 1984 Ridgecrest, California Ronald F. Vetter <[log in to unmask]> http://www.ridgecrest.ca.us/~rfvetter