Comparison of plasma, saliva, and hair lamotrigine concentrations.

BACKGROUND: 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. METHODS: 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. RESULTS: 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 < 0.001). Lamotrigine hair concentrations were correlated with the plasma concentrations (r = 0.53, p < 0.001) and daily dose in mg/kg (r = 0.23, p = 0.024). The analysis revealed no significant correlation between lamotrigine hair levels and the number of seizures in the previous 3 months (r = -0.1, p > 0.05). CONCLUSIONS: The lamotrigine saliva concentration is strongly correlated with its plasma level, and saliva can be used as an alternative matrix to plasma for monitoring. Lamotrigine can also be successfully measured in hair, and the drug levels in hair tend to be correlated with the levels in plasma. However, lamotrigine levels in hair may not correspond to clinical outcomes (i.e., seizure episodes).

Comparison of Plasma, Saliva, and Hair Levetiracetam Concentrations.

BACKGROUND: Previous findings revealed high correlations between serum/plasma and saliva levetiracetam concentrations, indicating saliva as an alternative matrix for monitoring levetiracetam therapy. Levetiracetam concentration in the hair, which could reflect long-term drug exposure and patients' compliance, has not been systematically tested, as yet. The aim of this study was to determine the correlation between plasma, saliva, and hair levetiracetam concentrations in 47 patients with epilepsy. METHODS: Plasma, saliva, and hair levetiracetam concentrations were measured by liquid chromatography-tandem mass spectrometry with positive ionization. RESULTS: Levetiracetam saliva and plasma concentrations were highly correlated (r = 0.93). Plasma concentrations were not influenced by sex, age, and other concomitant antiepileptic drugs. Levetiracetam hair concentrations correlated with plasma concentrations (r = 0.36) but not daily dose (mg/kg). Drug hair concentrations were not influenced by hair color or treatment (dyed). CONCLUSIONS: The results tend to indicate that saliva may be a reliable alternative to plasma for monitoring levetiracetam concentrations. Levetiracetam can also be detected in human hair.