title: Downbeat nystagmus as a result of lamotrigine toxicity.
abstract: BACKGROUND
  Downbeat nystagmus (DBN) has been reported with phenytoin and carbamazepine toxicity. DBN has not been described as a result of lamotrigine toxicity.
  
  
  METHODS
  Clinical records, neuroimaging and video recordings were obtained in two patients diagnosed with intractable epilepsy who developed oscillopsia and incoordination while being treated with lamotrigine. One patient had a videonystagmographic (VNG) study.
  
  
  CONCLUSIONS
  Lamotrigine's half-life is extended when used with valproic acid; hence, the increased chance of neurotoxicity associated with DBN. In our cases, DBN and truncal ataxia occurred in conjunction with toxic lamotrigine serum levels.
  
  
  CONCLUSIONS
  Anticonvulsant toxicity should be considered as a cause of DBN. Lamotrigine toxicity may be an unusual cause.
authors.affiliation: Department of Neurology, University of Illinois College of Medicine at Peoria, OSF Saint Francis Medical Center, 530N.E. Glen Oak Avenue, Peoria, IL 61637, USA. alkawi@uic.edu
authors.forename: Ammar
authors.initials: A
authors.lastname: Alkawi
authors.forename: Jorge C
authors.initials: JC
authors.lastname: Kattah
authors.forename: Katie
authors.initials: K
authors.lastname: Wyman
mesh_terms: D000328:Adult; D000927:Anticonvulsants / Q000097:blood / Q000633:toxicity*; D003952:Diagnostic Imaging / Q000379:methods; D005260:Female; D006801:Humans; D000077213:Lamotrigine; D009759:Nystagmus, Pathologic / Q000209:etiology*; D014227:Triazines / Q000097:blood / Q000633:toxicity*; D014741:Video Recording / Q000379:methods
chemical_list: D000927:Anticonvulsants; D014227:Triazines; D000077213:Lamotrigine