title: "On-off" effects in patients with Parkinson's disease on chronic levodopa therapy.
abstract: Fluctuations in performance in patients with Parkinson's disease on chronic levodopa therapy (the "on-off" effect) are due to several factors. The increasing severity during treatment of early morning akinesia, "freezing" episodes, and end-of-dose deterioration are probably due to progression of the underlying disease. Peak-dose dyskinesia and peak-dose akinesia are due to levodopa over dosage. "Yo-yo-ing", which is the severest form of such fluctuation in mobility and dyskinesias, may represent the sum of these disorders.
mesh_terms: D004305:Dose-Response Relationship, Drug; D006207:Half-Life; D007980:Levodopa / Q000008:administration & dosage* / Q000009:adverse effects / Q000097:blood / Q000627:therapeutic use; D008134:Long-Term Care; D009069:Movement Disorders / Q000139:chemically induced*; D009127:Muscle Rigidity / Q000139:chemically induced*; D010300:Parkinson Disease / Q000097:blood / Q000188:drug therapy*; D013997:Time Factors
chemical_list: D007980:Levodopa