Katharina Ebert1, Elena Maurice1, Richard Lukačin2, Christian Fleischhaker1, Eberhard Schulz1, Dieter Ebert3, Hans-Willi Clement1. 1. Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Centre for Mental Health, University Hospital of Freiburg, Freiburg. 2. Chromsystems Instruments & Chemicals GmbH, Gräfelfing. Dr. Lukacin is now with RECIPE Chemicals and Instruments GmbH, Munich, Germany. 3. Department of Psychiatry, Psychosomatics and Psychotherapy, Centre for Mental Health, University Hospital of Freiburg, Freiburg, Germany.
Abstract
BACKGROUND: Therapeutic drug monitoring has become increasingly important in psychiatric therapy. However, it is not yet implemented as a daily routine in clinical settings. To evaluate new, noninvasive procedures, we compared blood and saliva venlafaxine, quetiapine, and citalopram concentrations in samples collected from psychiatric patients. METHODS: We collected blood and saliva samples from 75 psychiatric patients (39 venlafaxine, 19 quetiapine, and 17 citalopram). Saliva sampling was achieved by the use of cotton pads. Venlafaxine (and its metabolite O-desmethylvenlafaxine) and quetiapine were analyzed by LC-MS/MS, whereas citalopram was analyzed by HPLC. RESULTS: We observed significant correlations between concentrations of venlafaxine (ratio saliva/serum ± SD: 18.3 ± 9.5, P < 0.01, r = 0.895) and its metabolite O-desmethylvenlafaxine (ratio saliva/serum ± SD: 4.1 ± 3.2, P < 0.05, r = 0.344), quetiapine (ratio saliva/serum ± SD: 0.2 ± 0.2, P < 0.01, r = 0.935), and citalopram (ratio saliva/serum ± SD: 2.6 ± 1.2, P < 0.05, r = 0.54) in serum and in saliva. Furthermore, measured concentrations of venlafaxine (and its metabolite O-desmethylvenlafaxine) and citalopram were higher in saliva than in serum, whereas measured concentrations of quetiapine were higher in serum than in saliva. CONCLUSIONS: Using cotton pad saliva sampling, venlafaxine and quetiapine demonstrate high correlations between saliva and serum concentrations, whereas for O-desmethylvenlafaxine and citalopram, other methods of sampling might be preferable. Saliva therapeutic drug monitoring of psychoactive drugs might become a useful approach to achieving individual treatment regimens.
BACKGROUND: Therapeutic drug monitoring has become increasingly important in psychiatric therapy. However, it is not yet implemented as a daily routine in clinical settings. To evaluate new, noninvasive procedures, we compared blood and saliva venlafaxine, quetiapine, and citalopram concentrations in samples collected from psychiatricpatients. METHODS: We collected blood and saliva samples from 75 psychiatricpatients (39 venlafaxine, 19 quetiapine, and 17 citalopram). Saliva sampling was achieved by the use of cotton pads. Venlafaxine (and its metabolite O-desmethylvenlafaxine) and quetiapine were analyzed by LC-MS/MS, whereas citalopram was analyzed by HPLC. RESULTS: We observed significant correlations between concentrations of venlafaxine (ratio saliva/serum ± SD: 18.3 ± 9.5, P < 0.01, r = 0.895) and its metabolite O-desmethylvenlafaxine (ratio saliva/serum ± SD: 4.1 ± 3.2, P < 0.05, r = 0.344), quetiapine (ratio saliva/serum ± SD: 0.2 ± 0.2, P < 0.01, r = 0.935), and citalopram (ratio saliva/serum ± SD: 2.6 ± 1.2, P < 0.05, r = 0.54) in serum and in saliva. Furthermore, measured concentrations of venlafaxine (and its metabolite O-desmethylvenlafaxine) and citalopram were higher in saliva than in serum, whereas measured concentrations of quetiapine were higher in serum than in saliva. CONCLUSIONS: Using cotton pad saliva sampling, venlafaxine and quetiapine demonstrate high correlations between saliva and serum concentrations, whereas for O-desmethylvenlafaxine and citalopram, other methods of sampling might be preferable. Saliva therapeutic drug monitoring of psychoactive drugs might become a useful approach to achieving individual treatment regimens.