Potential Drug Interactions Between Psychotropics and Intravenous Chemotherapeutics Used by Patients With Cancer

Abstract

Introduction: Patients undergoing cancer treatment usually have comorbidities, and psychiatric disorders are commonly seen in these patients. For the treatment of these psychiatric disorders, the use of psychotropic drugs is common, turning these patients susceptible to untoward drug interactions. Therefore, the aim of this study was to estimate the prevalence of clinically relevant drug–drug interactions (DDI) between chemotherapeutic and psychotropic agents in patients with cancer treated at an oncology service in southern Brazil. Methods: An observational epidemiological study with a cross-sectional census-type design was carried out between October and December 2020. The drug-drug interactions were identified through consultation and analysis of the Medscape Drug Interaction Check and Micromedex databases. The interactions were classified as major, when the interaction can be fatal and/or require medical intervention to avoid or minimize serious adverse effects and moderate, when the interaction can exacerbate the patient’s condition and/or requires changes in therapy. Results: A total of 74 patients was included in the study among the 194 patients seen in the oncology service during the period studied. A total of 24 (32.4%) DDIs were found, 21 (87.5%) of which were classified as being of major risk and 3 (12.5%) as moderate risk. According to the mechanism of action, 19 (79.1%) were classified as pharmacodynamic interactions and 5 (20.9%) as pharmacokinetic interactions. Conclusion: It was shown that a considerable percentage of patients undergoing intravenous chemotherapy are at risk of pharmacological interaction with psychotropic drugs. Thus, it is essential that the oncologist considers all psychotropic drugs and other drugs used by patients in order to avoid drug-drug interactions.

Insomnia among Cancer Patients in the Real World: Optimising Treatments and Tailored Therapies

“…Anticholinergic side effects of amitriptyline, especially constipation, should be kept in mind in patients taking opioids. Moreover, as other TCAs, amitriptyline could inhibit CYP2C19 threatening the efficacy of cyclophosphamide [32], and its administration with Oxaliplatin could lead to an increased risk of QT interval prolongation [49]. Moreover, hormone replacement therapy (oestrogens), cimetidine (inhibiting CYP1A), fluvoxamine, fluoxetine, paroxetine, bupropion, and duloxetine (inhibiting CYP2D6) could increase its blood levels.…”

“…In addition to the metabolic effects of these compounds, other side effects such as extrapyramidal symptoms, orthostatic hypotension, QTc interval prolongation, arrhythmias, and haematological consequences should be considered. In particular, quetiapine with oxaliplatin could determine an increased risk of QT interval prolongation [49]. Furthermore, and particularly important in breast cancer patients, antipsychotics could also lead to hyperprolactinemia.…”

“…A classic example of a pharmacokinetic interaction between psychiatric drugs and chemotherapeutics is the effect that SSRIs have on cytochrome CYP2D6 and the consequences for tamoxifen metabolism, reducing its clinical benefits [47]. These interactions may concern the relationship between other psychotropic drugs and chemotherapeutic agents [48,49]. Some of these interactions will be described below.…”

Drug–Drug interactions of docetaxel in patients with breast cancer based on insurance claims data

“…To the best of our knowledge, this study is the first to evaluate the prevalence of docetaxel drug-drug interactions using a nationwide database. Although direct comparisons are not possible due to the use of different study designs, anticancer agents, and databases, the two reported overall prevalences of DDIs for anticancer medications were 32.4% or 26.4%, and when limited to significant drug-drug interactions, the prevalences for anticancer medications were 28.4% or 9.7% [22,23].…”