Jack,

Thanks so much for the information.  Just to make sure I understand, are
you saying that:

        (A) It is better to take Sinemet CR with food? and
        (B) The effect of a Sinemet CR tablet will last longer if
            it is taken with food?

Thanks again.

Lynne
  for Virginia 81/17

"Jack J. Chen" wrote:
>
> Lynne,
> When it comes to food and Sinemet bioavailability, it can get confusing!
> I wrote a chapter on drug therapy for PD.
> Maybe I can help clarify and keep it simple.
> Ideally, Sinemet standard release is best absorbed on an empty stomach. This
> is because certain amino acids can reduce the bioavailablity of levodopa to
> body and brain.  (I need to explain something here.  Many of  you may take
> Sinemet on an empty stomach and find out that it turns your guts upside
> down. So your pharmacist or doctor might suggest to take with food).  Well,
> that's alright because what's the point of taking it on an empty stomach if
> it makes you vomit or get sick each time.  So it's a trade off between
> reduced bioavailability and no nausea. And if you're not getting enough of a
> kick, then the doctor can always increase the dose to compensate).
>
> Now, Sinemet CR is a different story.  The tablet matrix is made for
> sustained release of levodopa (that's why you shouldn't crush or chew the
> CR).  When you take Sinemet CR with food, the tablet is retained in the
> stomach longer.  This is good because the longer the tablet is in your
> stomach, the more levodopa gets released and is eventually absorbed in the
> small intestines. If you take Sinemet CR on an empty stomach, the tablet
> will pass through your stomach and small intestines before all the levodopa
> gets a chance escape from the tablet matrix.
>
> Hope this was helpful,
> Jack Chen, PharmD
>
> Lynne wrote:
>
> > Hi,
> >
> > I came across a paragraph of information about Sinemet that has really
> > confused me (of course it doesn't take much to confuse me :-)  Can
> > anyone help me understand what the paragraph means about bioavailability
> > and Cmax in plain English, or comment on whether there might be a
> > typographical error in the paragraph?  The paragraph is part of a
> > document about Sinemet on the "Clinical Pharmacology 2000" website:
> > http://cp.gsm.com.
> >
> > One example of what is confusing me:  It seems to say that food
> > **increases** the bioavailability and Cmax of levodopa in the Sinemet CR
> > tablet. [But then it says that food may decrease the absorption of
> > levodopa.]  Maybe I'm getting confused by terminology?  Here is the
> > paragraph:
> >
> > BEGIN QUOTE  Pharmacokinetics:  ...it is thought that high
> > concentrations of amino acids in the GI tract (i.e., a high-protein
> > diet) can interfere with absorption of levodopa.  There is evidence,
> > however, to suggest that amino acid-transport competition is more likely
> > to occur during levodopa transport across the blood-brain barrier.
> > [Snip...]  The bioavailability and Cmax of levodopa after a single dose
> > of a carbidopa 50 mg/levodopa 200 mg extended-release tablet increased
> > by 50% and 25%, respectively, when administered with food.  Any food
> > (i.e., high fat or high protein) or drug that delays gastric emptying
> > may decrease the absorption of levodopa.... END QUOTE
> >
> > Thanks for any hints about what this is about!
> >
> > Best,
> > Lynne
> >   for Virginia 80/17