Margaret, When I asked my doctor about drowsiness while driving and taking pramipexole, he replied that it was a side effect of sinemet CR. I reasoned that, since pramipexole "helps" sinemet work more efficiently, it also increases the negative as well as the positive. He was noncomittal on that. Whatever the reason, it seems to be a documented effect, so you're not imagining things. The late Alan Bonander noticed that the problem occurred about a half hour after a sinemet CR taken after a dose of pramipexole. Someone recommended chewing gum to keep the metabolism going, and that seems to help somewhat. With me, it doesn't just happen when I'm driving, though that's when the problem is most serious. I just have to sit down and be quiet for a few minutes and I lose consciousness. I literally "black out" for mini-seconds at a time, which is scary. Yet the boost I get from the medication is not something I want to give up. "Tis a dilemma. Pat Schark 57/11; 1.25mg 3X day