title: Levodopa-induced myoclonus.
abstract: Twelve parkinsonian patients on long-term levodopa therapy developed intermittent, myoclonic body jerks. The movements consisted of single unilateral or bilateral abrupt jerks of the extremities and occurred most frequently during sleep. Although directly related to daily dosage of levodopa, the myoclonus was specifically blocked by the serotonin antagonist, methysergide. Levodopa-induced myoclonus may be related to intermittent increases of activity of serotonin in the brain and results from levodopa-induced dysregulation of serotonin activity.
mesh_terms: D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000368:Aged; D000547:Amantadine / Q000627:therapeutic use; D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D001590:Benztropine / Q000627:therapeutic use; D018492:Dopamine Antagonists; D004305:Dose-Response Relationship, Drug; D005260:Female; D006168:Guinea Pigs / Q000378:metabolism; D006801:Humans; D007980:Levodopa / Q000009:adverse effects*; D008297:Male; D008784:Methysergide / Q000494:pharmacology; D008875:Middle Aged; D009069:Movement Disorders / Q000139:chemically induced; D009207:Myoclonus / Q000139:chemically induced* / Q000503:physiopathology; D010300:Parkinson Disease / Q000188:drug therapy; D011433:Propranolol / Q000627:therapeutic use; D012701:Serotonin / Q000009:adverse effects; D012702:Serotonin Antagonists; D012890:Sleep; D014282:Trihexyphenidyl / Q000627:therapeutic use
chemical_list: D018492:Dopamine Antagonists; D012702:Serotonin Antagonists; D001590:Benztropine; D012701:Serotonin; D007980:Levodopa; D014282:Trihexyphenidyl; D011433:Propranolol; D000547:Amantadine; D006916:5-Hydroxytryptophan; D000661:Amphetamine; D008784:Methysergide