The very first drug I was put on after my diagnosis was ropinerole [dopamine agonist]. It was only marginally effective. So my original neurologist kept bumping up the dosage until it made me vomit and have diarrhoea, cold sweats and such dizziness that the only thing I could do was lie down. The neurologist's solution was to put me on, in addition, anti-nausea medications permanently. Later, I self-discovered this class of anti-nausea drugs  are not supposed to be used long term.