Lora, what is causing the nausea is dopamine produced in the peripheral circulation from the L-DOPA. This is caused by enzyme peripheral dopa decarboxylase. What carbidopa is supposed to do is inhibit this enzyme so that more of the DOPA gets to the brain where the brain dopa decarboxylase converts it to dopamine where it does you some good. A little more carbidopa in the form of Lodosyn, taken with Sinemet might help, but I think Steve's and Donna's advice about slower increases in Sinemit dosages and a little non-protein food when you take it are probably the best approaches.

We are all wishing you the best possible outcome in this adventure (which none of us intended to begin)!

Robert