Levodopa-induced dyskinesias in Parkinson disease are independent of the extent of striatal dopaminergic denervation: a pharmacological and SPECT study.

The physiopathology of levodopa-induced dyskinesias (LIDs) is unclear. Presynaptic pharmacokinetic and postsynaptic pharmacodynamic mechanisms may be involved. We have analyzed several clinical and pharmacological parameters, as well as the status of the presynaptic dopamine nigrostriatal pathway by using DaTSCAN, in 14 patients with Parkinson disease who developed early and severe LID despite using low doses of levodopa and 10 patients without this complication despite the use of high levodopa doses.