Re: Sinemet pharmacokinetics question

["Jack J. Chen" <jackchen@xxxxxxxxx>]

Hello Lynne,
Yes, taking Sinemet CR with food should  provide a longer lasting effect.
I'm curious, has anyone out there noticed a difference when taking Sinemet CR 
with
food or without food?
Jack
PWOP

Lynne wrote:

> 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:
> > > .
> > >
> > > 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