Reactive metabolites of desipramine and clomipramine: The kinetics of formation and reactivity with DNA

Metabolic bioactivation of antidepressants: advance and underlying hepatotoxicity

Many drugs that serve as first-line medications for the treatment of depression are associated with severe side effects, including liver injury. Of the 34 antidepressants discussed in this review, four have been withdrawn from the market due to severe hepatotoxicity, and others carry boxed warnings for idiosyncratic liver toxicity. The clinical and economic implications of antidepressant-induced liver injury are substantial, but the underlying mechanisms remain elusive. Drug-induced liver injury may involve the host immune system, the parent drug, or its metabolites, and reactive drug metabolites are one of the most commonly referenced risk factors. Although the precise mechanism by which toxicity is induced may be difficult to determine, identifying reactive metabolites that cause toxicity can offer valuable insights for decreasing the bioactivation potential of candidates during the drug discovery process. A comprehensive understanding of drug metabolic pathways can mitigate adverse drug-drug interactions that may be caused by elevated formation of reactive metabolites. This review provides a comprehensive overview of the current state of knowledge on antidepressant bioactivation, the metabolizing enzymes responsible for the formation of reactive metabolites, and their potential implication in hepatotoxicity. This information can be a valuable resource for medicinal chemists, toxicologists, and clinicians engaged in the fields of antidepressant development, toxicity, and depression treatment.

Various species of Basidiomycota fungi reveal different abilities to degrade pharmaceuticals and also different pathways of degradation

The presence of pharmaceuticals (PhACs) in the aquatic environment is an emerging problem worldwide. PhACs reach surface water via the effluents of wastewater treatment plants (WWTPs). WWTPs, although able to remove organic pollutants, do not always remove PhACs. Currently, in the treatment of sewage with the activated sludge method, numerous microorganisms are used, mostly bacteria. Nevertheless, these microorganisms are not resistant to many drug contaminants, and some may also pose a risk to human health. White-rot fungi (WRF), which degrade a wide spectrum of environmental pollutants, may be used as an alternative to microorganisms. However, little data exists comparing the removal of various PhACs by different WRF. In this study, we aimed to determine the ability of three WRF Basidiomycota species, Armillaria mellea, Phanerochaete chrysosporium, and Pleurotus ostreatus, to remove PhACs from various therapeutic groups over the course of 1 h-4 days. Additionally, we identified the fungal metabolites of PhACs, proposed the degradation pathways, and assessed the toxicity of the post-culture media. All selected WRF removed PhACs, but the degree of removal depended on WRF species and PhACs type. Antidepressants and immunosuppressants were removed most efficiently by P. ostreatus, cardiovascular drugs and sulfamethoxazole by A. mellea, and erythromycin by P. chrysosporium. The vast differences observed highlight the need for more intensive testing of different WRF species to select the best species for removing pharmaceuticals of interest. The structure of metabolites generated during degradation strongly depended on WRF species, but the most frequent xenobiotic transformations were oxidation and dealkylation. The obtained results gave insight into the substrate specificity of selected WRF while also providing a broad extension of the knowledge of pharmaceutical degradation by A. mellea.

Application of Pleurotus ostreatus to efficient removal of selected antidepressants and immunosuppressant

Disposed pharmaceuticals constitute a significant threat to the environment due to the high consumption of drugs and inefficient treatment of wastewater. In this paper, we first described the efficient removal of a series of antidepressants and immunosuppressant from a cultivation medium carried out by white-rot fungus, Pleurotus ostreatus. We determined the removal efficiency of pharmaceuticals and the activity of fungal ligninolytic enzymes over time, as well as the toxicity of pre- and post-cultivation medium to Spirostomum ambiguum. We showed that P. ostreatus can remove from the model medium most of the pharmaceuticals studied, including clomipramine, mianserin, paroxetine, sertraline, and mycophenolic acid. Pharmaceuticals containing phenolic or benzene moieties, likewise in the natural monolignols, were removed in a high efficiency within a short time. The activity of the fungal ligninolytic enzymes, laccase, and lignin peroxidase, in the cultivation medium, was three times higher in the presence of the pharmaceuticals, which justifies their contribution to the degradation. The post-cultivation medium showed lower toxicity than pre-cultivation medium and toxic units were 7- and 2-fold lower for the sublethal and lethal response, respectively. Over twenty metabolites we detected resulted mostly from oxygenation or demethylation of parent pharmaceuticals. The biological treatment we developed using P. ostreatus-based system should be convenient and effective in mycoremediation of environmental wastewater polluted with emerging contaminants including monolignol-like antidepressants and immunosuppressant.

Antidepressants are cytotoxic to rat primary blood brain barrier endothelial cells at high therapeutic concentrations

Antidepressants are commonly employed for the treatment of major depressive disorders and other psychiatric conditions. We investigated the relatively acute cytotoxic effects of three commonly prescribed antidepressants: fluoxetine, sertraline, and clomipramine on rat primary blood brain barrier endothelial cells over a concentration range of 0.1-100μM. At therapeutic concentrations (0.1μM) no significant cytotoxicity was observed after 4, 24, or 48h. At high therapeutic to overdose concentrations (1-100μM), antidepressants reduced cell viability in proportion to their concentration and exposure duration. At 1μM, antidepressants significantly reduced mitochondrial membrane potential. At drug concentrations producing ~50% inhibition of cell viability, all drugs significantly reduced cellular oxygen consumption rates, activities of mitochondrial complexes I and III, and triggered a significant increase of lactate production. Fluoxetine (6.5μM) and clomipramine (5.5μM) also significantly lowered transcellular transport of albumin. The mechanism of cellular cytotoxicity was evaluated and at high concentrations all drugs significantly increased the production of reactive oxygen species, and significantly increased the activity of the pro-apoptotic caspases-3, 8, and 9. Comet assays revealed that all drugs were genotoxic. Pre-incubation of cells with glutathione significantly ameliorated antidepressant-induced cytotoxicity, indicating the potential benefit of treatment of overdosed patients with antioxidants.