Comparison of plasma, saliva, and hair lamotrigine concentrations

In some clinical situations (pregnancy, aging, drug resistance, toxicity), measurements of lamotrigine plasma levels may be reliable. Limited studies indicate that saliva and hair could be alternative sources for monitoring lamotrigine therapy. The drug content in hair can also be used to assess the history of drug therapy and to ascertain long-term patient compliance. The aims of this study were to 1) determine the correlations among plasma, saliva, and hair lamotrigine concentrations, 2) evaluate saliva as an alternative matrix for monitoring drug levels and 3) evaluate hair as a source of information on adherence to antiepileptic treatment and on the correlation of hair concentrations with clinical outcomes in patients with epilepsy. Plasma, saliva, and hair lamotrigine concentrations were measured by liquid chromatography–tandem mass spectrometry in positive ionization mode. The study group (n = 85) was recruited among the epileptic patients at the Institute of Psychiatry and Neurology, Warsaw, Poland. Plasma concentrations were not influenced by sex, age, or the concomitant use of other antiepileptic drugs. Lamotrigine saliva and plasma concentrations were strongly correlated (r = 0.82, p