Monitoring salivary lamotrigine concentrations.
Lamotrigine concentrations were measured simultaneously (as far as was feasible) in stimulated and unstimulated saliva samples, and in plasma, from seven adult volunteers over a 32 h period following a single 50 mg dose of the drug, and in 20 children and adolescents during the course of routine antiepileptic therapy. In individuals there was a close correlation between the measurements at least 2 h after ingestion of the drug. Concentrations in stimulated and unstimulated saliva were similar; the stimulation produced little change in the saliva secretion rate. The saliva-to-plasma concentration ratio increased linearly by 0.78% for each 1 mg/L plasma lamotrigine concentration, with a mean value of 48.8% at a plasma lamotrigine concentration of 10 mg/L. With appropriate precautions as to the timing of saliva collections, and a single plasma lamotrigine concentration measurement to calibrate the salivary values in the individual, salivary lamotrigine concentration measurement appears to be a practicable approach to therapeutic drug monitoring. This has significant implications for the elucidation of the pharmacokinetics of lamotrigine in the paediatric population.
Malone
Stephen A
SA
Royal Children's Hospital, Brisbane, Queensland, Australia.
Eadie
Mervyn J
MJ
Addison
Russell S
RS
Wright
Andrew W E
AW
Dickinson
Ronald G
RG
D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics; D001681:Biological Assay / Q000379:methods; D002648:Child; D002675:Child, Preschool; D004334:Drug Administration Schedule; D004827:Epilepsy / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007223:Infant; D000077213:Lamotrigine; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D010949:Plasma / Q000737:chemistry; D012463:Saliva / Q000737:chemistry*; D013997:Time Factors; D014227:Triazines / Q000032:analysis* / Q000097:blood / Q000493:pharmacokinetics
D000927:Anticonvulsants; D014227:Triazines; D000077213:Lamotrigine