Tamoxifen and serotonin reuptake inhibitors: Risks and benefits of co-administration

Tamoxifen citrate is a nonsteroidal compound belonging to the triphenylethylene class, characterized by a complex spectrum of pharmacological effects, acting as an estrogen antagonist or agonist depending on the tissue. In breast cancer patients, tamoxifen predominantly exerts an anti-estrogenic action on tumor tissue by inhibiting the binding of estrogen to its receptors. Tamoxifen is metabolized in the liver by the cytochrome P450 enzymatic system, resulting in active metabolites. The CYP2D6 enzyme plays a crucial role in the metabolism of approximately 25% of exogenous drugs, including tamoxifen, being considered the primary enzyme involved in the bioactivation of this therapeutic agent. This study aims to understand the metabolism of tamoxifen mediated by the cytochrome P450 system, particularly CYP2D6, which is essential for optimizing its clinical use and allowing treatment personalization based on the patient’s individual metabolic profile. This literature review was conducted through the analysis of articles published in the last five years or of significant impact in the field, focusing on drug interactions and the management of depressive symptoms during oncological treatment. Measures are essential to mitigate the risks associated with drug interactions. Some studies recommend reviewing pharmacotherapy, considering not only antineoplastic drugs but also complementary, alternative therapies and the use of over-the-counter medications to reduce the number of substances administered. Furthermore, the early identification of potential interactions is crucial, enabling appropriate and proactive clinical management. Thus, an in-depth understanding of CYP2D6 pharmacogenomics and the adoption of evidence-based clinical strategies are indispensable for optimizing tamoxifen treatment, preserving its efficacy, and minimizing the risks associated with drug interactions