title: Donepezil-induced myoclonus in a patient with Alzheimer disease.
abstract: OBJECTIVE
  To report an uncommon adverse event in an elderly patient related to the cholinesterase inhibitor, donepezil.
  
  
  METHODS
  An 80-year-old Greek woman with Alzheimer disease was admitted to the hospital with a sudden onset of myoclonus in both upper and lower extremities after receiving 30 mg of donepezil daily for 25 days. After 36 hours of donepezil remission, the frequency of the myoclonic jerks was sharply reduced. The patient remains asymptomatic after 6 months of follow-up.
  
  
  CONCLUSIONS
  Our literature search yielded only 2 cases of myoclonus in relation to memantine, which has a different action with donepezil; to our knowledge, this is the first report of generalized myoclonus induced by donepezil overdosing. Based on the Naranjo probability scale it was probable that the patient's myoclonus was related to donepezil because of clear temporal proximity and lack of alternative explanations.
  
  
  CONCLUSIONS
  Clinicians should take into consideration therapeutic drug monitoring in the event of a potentially rare serious adverse reaction. Further studies are needed to clarify the possible role of donepezil in the pathophysiology of myoclonus.
authors.affiliation: University of Athens Medical School, Aeginition Hospital, Athens, Greece annita139@yahoo.gr.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Bougea
authors.affiliation: University of Athens Medical School, Aeginition Hospital, Athens, Greece.
authors.forename: Stathis
authors.initials: S
authors.lastname: Gerakoulis
authors.affiliation: University of Athens Medical School, Aeginition Hospital, Athens, Greece.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Anagnostou
authors.affiliation: University of Athens Medical School, Aeginition Hospital, Athens, Greece.
authors.forename: George
authors.initials: G
authors.lastname: Paraskevas
authors.affiliation: University of Athens Medical School, Aeginition Hospital, Athens, Greece.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kapaki
authors.affiliation: University of Athens Medical School, Aeginition Hospital, Athens, Greece.
authors.forename: Evangelia
authors.initials: E
authors.lastname: Kararizou
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000188:drug therapy*; D002800:Cholinesterase Inhibitors / Q000009:adverse effects*; D000077265:Donepezil; D005260:Female; D006801:Humans; D007189:Indans / Q000009:adverse effects*; D009207:Myoclonus / Q000139:chemically induced*; D010880:Piperidines / Q000009:adverse effects*
chemical_list: D002800:Cholinesterase Inhibitors; D007189:Indans; D010880:Piperidines; D000077265:Donepezil
keywords: Alzheimer disease; adverse effects; cholinesterase inhibitors; clinical trials; donepezil; myoclonus