Correlation of lamotrigine concentrations between serum and saliva.
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.
Ryan
Melody
M
University of Kentucky Chandler Medical Center, Lexington 40536-0293, USA.
Grim
Shellee A
SA
Miles
Michael V
MV
Tang
Peter H
PH
Fakhoury
Toufic A
TA
Strawsburg
Richard H
RH
deGrauw
Ton J
TJ
Baumann
Robert J
RJ
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
D000927:Anticonvulsants; D014227:Triazines; D000077213:Lamotrigine