title: [Interchangeability among therapeutics equivalents of lamotrigine in the treatment of refractory epilepsy patients: risks and benefits].
abstract: BACKGROUND
  Epilepsy is a condition characterized by signs and symptoms of neurological disorder. Lamotrigine has been widely used, mainly due to their greater tolerability and lower rate of drug interactions with other antiepileptic drugs however the newest antiepileptic drugs have high cost to patient. In Brazil there are three different sort of pharmaceutical equivalents (reference, generic and similar), and the Brazilian health care authorities offers to users the possibility to receive them free of charge. Moreover these pharmaceutical equivalents can change during the treatment of epilepsy because this authorities buy the cheapest by public tender two or three times a year.
  
  
  OBJECTIVE
  To evaluate the clinical and laboratory findings related to the most frequently used therapeutic equivalents of lamotrigine (reference drugs and similar products).
  
  
  METHODS
  Two similar formulations (A and B) and one reference (C) were tested in nine epileptic refractory patients. The study was divided into three periods of 42 days, one for each formulation, and medical data about the frequency of seizures, the occurrence of side effects and measurement of plasma concentrations of lamotrigine were collected.
  
  
  RESULTS
  The average number of seizures/week and plasma concentration of lamotrigine for formulations A, B and C were not statistically significant differences. Three patients during the use of the formulation C presented mild and transitory side effects.
  
  
  CONCLUSIONS
  Similar or reference drugs showed satisfactory results, however the interchangeability among the formulations raise the difficulty for the management of seizures in refractory epilepsy.
authors.affiliation: Departamento de Ciencias Farmacéuticas, Facultad de Ciencias Farmacéuticas de Ribeirão Preto, Universidad de São Paulo, Ribeirão Preto, São Paulo, Brasil.
authors.forename: Beatriz M P
authors.initials: BM
authors.lastname: Girolineto
authors.forename: Veriano
authors.initials: V
authors.lastname: Alexandre
authors.forename: Regina H C
authors.initials: RH
authors.lastname: Queiroz
authors.forename: Fausto
authors.initials: F
authors.lastname: Feletti
authors.forename: Américo C
authors.initials: AC
authors.lastname: Sakamoto
authors.forename: Leonardo R L
authors.initials: LR
authors.lastname: Pereira
mesh_terms: D000328:Adult; D000927:Anticonvulsants / Q000191:economics / Q000493:pharmacokinetics / Q000627:therapeutic use; D001938:Brazil; D004304:Dosage Forms; D004827:Epilepsy / Q000188:drug therapy*; D005260:Female; D006801:Humans; D000077213:Lamotrigine; D008297:Male; D008875:Middle Aged; D013810:Therapeutic Equivalency; D016896:Treatment Outcome; D014227:Triazines / Q000191:economics / Q000493:pharmacokinetics / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D000927:Anticonvulsants; D004304:Dosage Forms; D014227:Triazines; D000077213:Lamotrigine