Differences in Duloxetine Dosing Strategies in Smoking and Nonsmoking Patients

September 22, 2018

Marc Augustin, Georgios Schoretsanitis, Christoph Hiemke, Gerhard Gründer, Ekkehard Haen, Michael Paulzen

Journal of Clinical Psychiatry 2018 September 4, 79 (5)


BACKGROUND: For certain psychotropic drugs, such as clozapine or olanzapine, the influence of smoking on drug metabolism is well studied. Tobacco smoke increases the metabolism of drugs that are substrates for cytochrome P450 (CYP) 1A2 due to CYP induction. The antidepressant duloxetine, acting as a serotonin-norepinephrine reuptake inhibitor, is mainly metabolized via CYP1A2. To date, little is known about the influence of smoking on serum duloxetine concentrations.


METHODS: A therapeutic drug monitoring database consisting of plasma concentrations of duloxetine collected from January 2013 to June 2017 was analyzed. A group of nonsmoking patients undergoing treatment with duloxetine (n = 89) was compared to a group of active smokers also receiving duloxetine (n = 36). Serum concentrations of duloxetine and dose-adjusted serum concentrations were compared using non-parametric tests.


RESULTS: Groups did not differ concerning sex (P = .063), but the group of active smokers was younger (P < .001) and received higher daily doses of duloxetine (P = .001). Smokers showed significantly lower median serum duloxetine concentrations (38.4% lower, P = .002) and 53.6% lower dose-adjusted serum concentrations (0.325 [ng/mL]/[mg/d] in smokers vs 0.7 [ng/mL]/[mg/d] in nonsmokers, P < .001).


CONCLUSIONS: Despite higher daily doses, smokers had considerably lower serum duloxetine concentrations. The induction of CYP1A2 by tobacco smoke is a clinically relevant factor for drugs that are substrates for CYP1A2. Clinicians should actively assess smoking status, inform patients about the effect of smoking on duloxetine metabolism, and anticipate higher serum concentrations in the case of smoking cessation. Therapeutic drug monitoring ensures treatment efficacy by enabling the personalizing of treatment, as smokers need higher duloxetine doses to target serum concentrations within the therapeutic reference range.

Please reload

Our Recent Posts

"Anna-Sophie Rommel, Veerle Bergink, Xiaoqin Liu, Trine Munk-Olsen, Nina Maren Molenaar

Journal of Clinical Psychiatry 2020 May 12, 81 (3)


"Long-Term Effects of Intrauterine Exposure to Antidepressants on Physical, Neurodevelopmental, and Psychiatric Outcomes: A Systematic Review&quo...

May 21, 2020

Below is an updated consent for telehealth; you can obtain the official form from my assistant Eric Scott Kincaid.  I added in the following (listed a...

Updated Consent for Telehealth

March 24, 2020

Hi everyone,

I know you’re all closely watching the new developments in the COVID-19 pandemic and I imagine you’ve seen the recent guidelines that sugg...

COVID-19/coronavirus update

March 15, 2020

Please reload


I'm busy working on my blog posts. Watch this space!

Please reload




(917) 441-2344

PayPal can be used to send payment for services:

©2018 by Mark W. Wilson, MD, PC. Proudly created with Wix.com