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