title: The risk of paradoxical levetiracetam effect is increased in mentally retarded patients.
abstract: OBJECTIVE
  Incidental paradoxical antiepileptic effect of levetiracetam has been described. The aim of the present study was to identify the epilepsy patients at risk.
  
  
  METHODS
  We performed a retrospective analysis in 207 patients treated with levetiracetam. This entailed evaluation of patient notes and patient interviews. A paradoxical effect was defined as an increased seizure frequency or the experience of more severe seizures including generalized tonic-clonic seizures (GTCS) within 1 month after starting levetiracetam (LEV).
  
  
  RESULTS
  Thirty patients (14%) experienced a paradoxical effect. Eight of them (4%) developed de novo GTCS. We could not demonstrate any association between the paradoxical effect of levetiracetam and type of epilepsy or the antiepileptic comedication used. However we found that the paradoxical effect developed preferentially (p < 0.001) in mentally retarded patients.
  
  
  CONCLUSIONS
  Because there is an increased risk of worsening epilepsy when starting levetiracetam treatment of mentally retarded epileptic patients, there is a need for caution and close observation during the first weeks of therapy.
authors.affiliation: Epilepsy Center, National Institute of Neurosurgery, Budapest, Hungary. szucsan@gmail.com
authors.forename: Anna
authors.initials: A
authors.lastname: Szucs
authors.forename: Zsófia
authors.initials: Z
authors.lastname: Clemens
authors.forename: Rita
authors.initials: R
authors.lastname: Jakus
authors.forename: György
authors.initials: G
authors.lastname: Rásonyi
authors.forename: Daniel
authors.initials: D
authors.lastname: Fabó
authors.forename: András
authors.initials: A
authors.lastname: Holló
authors.forename: Gábor
authors.initials: G
authors.lastname: Barcs
authors.forename: Anna
authors.initials: A
authors.lastname: Kelemen
authors.forename: József
authors.initials: J
authors.lastname: Janszky
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000927:Anticonvulsants / Q000009:adverse effects* / Q000627:therapeutic use; D002648:Child; D006970:Disorders of Excessive Somnolence / Q000139:chemically induced / Q000453:epidemiology; D004244:Dizziness / Q000139:chemically induced / Q000453:epidemiology; D004347:Drug Interactions; D004827:Epilepsy / Q000188:drug therapy* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000453:epidemiology*; D007508:Irritable Mood / Q000187:drug effects; D000077287:Levetiracetam; D008297:Male; D008875:Middle Aged; D010889:Piracetam / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D000927:Anticonvulsants; D000077287:Levetiracetam; D010889:Piracetam