Therapeutic drug monitoring of venlafaxine in real-world patients: Dose, concentration and therapeutic efficacy

Introduction Venlafaxine (VEN) is an antidepressant prescribed for major depression, anxiety and panic disorders. The currently recommended reference range for VEN is 100–400 ng/ml, referring to the sum of VEN and its active metabolite O-desmethylvenlafaxine (ODV). High interindividual variability of VEN and ODV presents a challenge for an effective and safe pharmacotherapy. Therapeutic Drug Monitoring (TDM) is an affordable tool for optimizing outcomes in daily clinical practice. Methods One level per patient, the most current level, measured in steady state, was used. Additional data included information on age, sex, vital signs, comedication, addictive substances, liver- and kidney function, adverse drug reactions (ADR) and additional therapies. Dose-adjusted serum concentrations were computed to assess pharmacokinetic variability of VEN and ODV. TDM data of patients for whom treatment efficacy was assumed by VEN treatment at the time of discharge were compared to patients with medication switch. Results VEN and ODV concentrations were derived from patients at the Central Institute of Mental Health, for whom drug level measurement was requested under the treatment with VEN within the time period of 2014 to 2018. A total of 1808 drug level measurements from about 800 patients were assessed. Steady state levels were available for about 75% of these patients. Concentration results will be presented at the conference. Conclusion A high interindividual variability is expected in patients treated with VEN. Most patients are treated with concomitant medication potentially interfering with VEN and ODV metabolism. TDM is a valuable tool to address these issues. Publication History Article published online: 08 November 2022 © 2022. Thieme. All rights reserved. Georg Thieme Verlag Rüdigerstraße 14, 70469 Stuttgart, Germany