title: Correlation of lamotrigine concentrations between serum and saliva.
abstract: OBJECTIVE
  To compare the relationship between serum and salivary concentrations of lamotrigine in pediatric and adult epilepsy populations.
  
  
  METHODS
  Paired-sample pharmacokinetic study.
  
  
  METHODS
  University neurology clinic.
  
  
  METHODS
  Thirty-seven patients with epilepsy, aged 2-60 years, who were taking lamotrigine and whose physicians had ordered a lamotrigine serum concentration.
  
  
  RESULTS
  Patients spit a minimum of 0.25 ml into a cup to provide saliva samples. Blood samples were obtained by phlebotomy. Serum and salivary lamotrigine concentrations were determined by high-performance liquid chromatography. Linear regression analysis was used to evaluate correlations. Six patients' results were omitted due to the lack of a serum or saliva specimen or clearly erroneous results, leaving 31 patients for analysis. There was a strong correlation between the serum results reported by two reference laboratories (coefficient of correlation [r] = 0.988). The correlations between salivary and serum lamotrigine concentrations were similar for reference laboratory A (r = 0.81) and reference laboratory B (r = 0.84). Saliva:serum concentration ratios ranged from 0.41-1.26 (mean +/- SD 0.62 +/- 0.19) for reference laboratory A and from 0.40-1.19 ((mean +/- SD 0.64 +/- 0.18) for reference laboratory B.
  
  
  CONCLUSIONS
  There is a good correlation between salivary and serum concentrations for lamotrigine. However, there is wide interpatient variability in the saliva:serum ratio. The data suggest that salivary monitoring may play a role in the monitoring of lamotrigine for adult and pediatric patients.
authors.affiliation: University of Kentucky Chandler Medical Center, Lexington 40536-0293, USA.
authors.forename: Melody
authors.initials: M
authors.lastname: Ryan
authors.forename: Shellee A
authors.initials: SA
authors.lastname: Grim
authors.forename: Michael V
authors.initials: MV
authors.lastname: Miles
authors.forename: Peter H
authors.initials: PH
authors.lastname: Tang
authors.forename: Toufic A
authors.initials: TA
authors.lastname: Fakhoury
authors.forename: Richard H
authors.initials: RH
authors.lastname: Strawsburg
authors.forename: Ton J
authors.initials: TJ
authors.lastname: deGrauw
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Baumann
mesh_terms: D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000032:analysis* / Q000097:blood; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D016903:Drug Monitoring / Q000379:methods; D004827:Epilepsy / Q000188:drug therapy; D005260:Female; D006801:Humans; D000077213:Lamotrigine; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012463:Saliva / Q000737:chemistry*; D014227:Triazines / Q000032:analysis* / Q000097:blood
chemical_list: D000927:Anticonvulsants; D014227:Triazines; D000077213:Lamotrigine