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It should be noted that Lodosyn is not referenced in the 1995 PDR. That could mean it has been removed from the market. The use of Lodosyn, carbidopa only pills, seems to be warranted with the first Sinemet CR in the morning. The erosion (release) of medicine of the Sinemet CR differs depending on the drug in question. Carbidopa is released slower than the release of Levodopa. The result can be nausea for some patients. The way to avoid this problem is to take a Lodosyn pill with the first Sinemet CR. From the 1995 PDR, Page 960, column 3 "Dosage and Administration The optimum daily dosage of Sinemet must be determined by careful titration in each patient. Sinemet tablets are available in a 1:4 ratio of carbidopa to levodopa (sinemet 25/100) as well as 1:10 ratio (Sinemet 10/100 and Sinemet 25/250). Tablets of the two ratios may be given separately or combined as needed to provide the optimum dosage. Studies show that peripheral dopa decarboxylase is saturated by carbidopa at approximately 70 to 100 mg a day. Patients receiving less than this amount of carbidopa are more likely to experience nausea and vomiting." It goes on to say that Sinemet 25/100 should start at 3 tablets per day and may increase to 8 tablets per day. The use of Sinemet 10/100 should start at 3-4 tablets per day and may increase to 12 tablets per day. This gives an upper limit of about 200 mg of carbidopa per day. Sinemet CR In reading the material on Sinemet CR, less is mentioned about the use of carbidopa. It even states that patients taking as much as 1800 to 2400 mg of levodopa can use the controlled release. This would imply 9 to 12 pills or 450 mg to 600 mg of carbidopa if all pills are Sinemet CR 50/200. I do not use Sinemet CR, but in working with patients taking 4 or more Sinemet CR 50/200 plus some regular Sinemet, they experience some of the adverse effects of over dosage. How much of this is attributed to carbidopa and how much is levodopa is not known. I once had it explained to me that carbidopa inhibits the natural production of serotonin. On the other side, serotonin is very key in the natural production of dopamine. If all this is true, than excessive carbidopa would have the effect of reduced levels of serotonin (depression) and reduced production of natural dopamine. Whether this reduction could be compensated by the additional levodopa is not known. It could actually reduce the availability of total levodopa, It could account for the statement made sometime ago that implied dosage above 300 mg of carbidopa acts like it crosses the blood brain barrier and inhibits the conversion of levodopa to dopamine. If that doesn't confuse you, nothing will. Regards, Alan