Factors Affecting the Pharmacokinetics of Escitalopram – Data from a Naturalistic Study

The role of epigenetic factors on the pharmacokinetics of escitalopram (S-CIT) was analysed. Methods: In patients treated with S-CIT under naturalistic conditions steady state plasma concentrations of S-CIT and the major metabolite S-demethylcitalopram (S-D-CIT) were estimated. Trough drug levels were related to dose, age, gender, comedication and addiction comorbidity. Results: Primary diagnoses of the patients (n=201) were affective disorders (53%, f>m), anxiety and somatoform disorders (14%, m>f). The most frequent daily dose of S-CIT was 10mg/day (49%). Most patients were under polypharmacotherapy (84.4%). The mean dose corrected plasma concentrations (C/D ratio) of S-CIT under monotherapy (n=31) was 2.0±1,4ng/ml/mg. Under 20mg, plasma levels were significantly higher in females than in males. Correlation studies showed a significant positive relation of age and C/D ratio of S-CIT. Alcohol dependence associated with pathological liver changes did not influence blood levels of S-CIT, but severe cirrhosis. Polypharmacotherapy lead to slightly but not significantly lower C/D of S-CIT. In benzodiazepine dependent patients the C/D ratio of S-D-CIT was significantly higher than under monotherapy. Conclusion: This naturalistic study revealed that age, gender and chronic benzodiazepines intake affect pharmacokinetics of S-CIT.