Re: Sinemet

[Brian Collins <bjc@xxxxxxxxxxxxxxx>]

On Tue 25 Jan, William A. Parrette wrote:
> Hi all,
>
>         On Mon, 24 Jan 2000, the digest contained:
>
> > ...
> > Date:    Mon, 24 Jan 2000 11:01:27 -0500
> > From:    "Hawkins, Darwin" <Darwin.Hawkins@xxxxxxxxxxxxxxxxxx>
> > Subject: Re: Sinemet
> >
> > Would taking one 25/100 every 3 hours be closer to approximating the desired
> > effect of one 50/200 every 6 hours? Seems to me it would smooth things out.
> > ...
>
>         First, let me say (as has been said before) everybody's physi-
>      ology is different and different medications rarely have the same
>      effect on two different people.  This is especially true with PW-
>      Ps and Sinemet.
>
>         That being said:
>
>         25 mg. Carbidopa/100 mg. Levodopa x 8 (every 3 hours) =
>                               200 mg. Carbidopa/800 mg. Levodopa a day
>
>         50 mg. Carbidopa/200 mg. Levodopa x 4 (every 6 hours) =
>                               200 mg. Carbidopa/800 mg. Levodopa a day
>
>         And, although apparently the same levels of each ingredient is
>      being used, the regular Sinemet delivery would have  "spikes"  in
>      its  delivery-graph  and effectiveness.  Where the CR (controlled
>      release) version's delivery-graph would be smoother.  In  theory,
>      the  delivery of the CR is spread out more evenly over its effec-
>      tive period which results in a more even control of the  tremors;
>      where  the non-CR version would result in more control soon after
>      the dose was taken and less control toward the end of its  effec-
>      tive period.
>
>         If I remember correctly, the delivery-graphs for both products
>      are available at:
>
>                          
>
>         But, then again, all us PWPs is different ... :-)



I must write a few words to try and bring a degree of consistency to the
discussion about Sinemet tablets, in particular the CR200/50, CR100/25 and
plain Sinemet 100/25.

The first thing to understand is that the effective duration of any of the
types of tablet mentioned here is totally outside the control of the PWP.

The effective duration of these tablets is controlled for the most part by
the particular characteristics ofthe PWP's digestive system, with
contributions from the lower intestine, the blood system, and the
blood/Brain barrier. In addition, a newly-diagnosed PWP will tend to get
a longer period of effectiveness than a long-term PWP. As you will see,
none of those variables can be altered by us, to suit some drug schedule
which we have dreamed-up. I would estimate that at least half the drug
schedules that I see fail to recognise this single, fundamental fact.
For example; Sinemet 100/25 has (for me) an effective duration of 2 hours.
If I was told to take one tablet every 4 hours and did so, I would get
a situation in which I got the full dose of levodopa over the first 2
hours, and then 2 hours of NOTHING until the next tablet is taken.
This is just about the worst thing to do to a system trying to stay 'ON'
without the worry of dyskinesias: You will get the dyskinesias during the
first 2 hours, but suffer from a total 'OFF' during the second 2 hours.

So what can you do? It is quite simple really, you experiment on yourself.
Yes, here we go again- it is dangerous to fiddle with your drugs etc. etc.
so alright, ask your neuro to administer the tests - you may both learn
something. All you want to know is what is your 'Magic Number' - the time
interval which, if you take one Sinemet 100/25 at that rate, will give you
a constant, uninterrupted flow of effectiveness. Only then, can you think
about tailoring the size of the dose.

For the CR tablets, the principle is exactly the same, except that the
CR200 (in my tests) had an effective life of 4 hours, giving an excellent
50 mg/hour flow rate. When I did these tests (about 7 or 8 years ago),
there were no CR100 tablets available from Sinemet. There were some
Madopar CR100/25 however, so I tried those and was impressed to see that
the CR100 lasted the same time - 4 hours, and at all points delivered
exactly half the amounr of levadopa as the Sinemet CR200/50. I wouldn't be
at all surprised to find that the new Sinemet CR100/25 was the same, in
which case you can simply take two CR100s and get exactly the same result
as if you took 1 CR200.

Since that answers the original question, I will stop there. Further
reading can be found on  Simon Cole's Web site
Regards,

     http://james.parkinsons.org.uk/brian.htm
--
Brian Collins  <bjc@xxxxxxxxxxxxxxx>  (59/39/34)