• Katarzyna Karaś-Ruszczyk, Julita Kuczyńska, Halina Sienkiewicz-Jarosz, Iwona Kurkowska-Jastrzębska, Przemyslaw Bienkowski, Magdalena Restel, Jerzy Samochowiec, and Pawel Mierzejewski.
• *Department of Pharmacology,†1st Department of Neurology, and‡2nd Department of Neurology, Institute of Psychiatry and Neurology, Warsaw;§Department of Psychiatry, Warsaw Medical University, Warsaw; and‖Department of Psychiatry, Pomeranian Medical University, Szczecin, Poland.
• Ther Drug Monit. 2017 Jun 1; 39 (3): 263-268.

BackgroundPrevious 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.MethodsPlasma, saliva, and hair levetiracetam concentrations were measured by liquid chromatography-tandem mass spectrometry with positive ionization.ResultsLevetiracetam 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).ConclusionsThe 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.

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