I noted this was an old post, but nonetheless one still of interest. I too go off and have a short (15-20 min) of nausea about 15 to 30 min. after taking my meds....This is totally an uneducated guess, but due to the size of the levodopa molecule we have to take a larger than necessary dose to penetrate the blood brain barrier (BBB). Basically, the meds temporarily puts our bodies in a toxic state, in order to get sufficient L-dopa across the BBB.

Am I close in my understanding of this?

Peggy