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

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.