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Smoking Is Associated With Lower Dose–Corrected Serum Concentrations of Escitalopram

Scherf-Clavel, Maike PhD; Deckert, Jürgen MD; Menke, Andreas MD; Unterecker, Stefan MD

Journal of Clinical Psychopharmacology: September/October 2019 - Volume 39 - Issue 5 - p 485–488
doi: 10.1097/JCP.0000000000001080
Brief Reports

Background Tobacco smoking rates in depressive patients are higher compared with the general population. Smoking was demonstrated to accelerate the metabolism of different drugs metabolized by CYP1A2, but possibly also by CYP2C19 and CYP3A4. The principle aim of the present investigation from 2015 to 2018 was to determine the differences in the pharmacokinetics of escitalopram between smokers and nonsmokers.

Methods A group of nonsmokers (n = 88) was compared with smokers (n = 36), both receiving escitalopram, using the Mann-Whitney U test. Linear regression analysis was used to account for the impact of escitalopram dose, age, and sex in addition to smoking on the steady-state serum concentration of escitalopram.

Results Smokers received by mean 17.6% higher doses of escitalopram (P = 0.026) but showed 31.9% lower serum concentrations (P = 0.031). To control for confounders, linear regression analysis showed that dose (P < 0.001), sex (P = 0.03), and smoking tobacco (P = 0.027) did significantly influence serum concentrations of escitalopram with higher levels in women and nonsmokers.

Conclusions Notwithstanding higher daily doses, smokers had significantly lower serum concentrations of escitalopram. In concordance with previous results, besides CYP1A2, a possible induction of CYP2C19 and CYP3A4 by tobacco smoke, resulting in lower serum concentrations of escitalopram in smokers than in nonsmokers, is suggested. Therefore, to provide personalized therapy, clinicians should consider smoking status and inform patients on the interactions of smoking and escitalopram metabolism.

From the Department of Psychiatry, Psychosomatics and Psychotherapy, University Hospital of Würzburg, Würzburg, Germany.

Received March 4, 2019; accepted after revision June 1, 2019.

Reprints: Maike Scherf-Clavel, PhD, Department of Psychiatry, Psychosomatics and Psychotherapy, University Hospital of Würzburg, Margarete-Höppel-Platz 1, 97080 Würzburg, Germany (e-mail:

Andreas Menke and Stefan Unterecker contributed equally to this work.

Ethical approval: All procedures performed in the analysis involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. For this type of study (retrospective analysis with anonymous naturalistic data), formal consent is not required.

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Online date: July 23, 2019

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