Interactions of antidepressants with concomitant medications-safety of complex therapies in multimorbidities

Depression is the fourth most serious disease in the world. Left untreated, it is a cause of suicide attempts, emergence or exacerbation worsening of serious diseases, bodily and mental disorders, as well as increased risk of cardiovascular diseases, stroke, diabetes, and obesity, as well as endocrine and neurological diseases. Frequent coexistence of depression and other diseases requires the simultaneous use of several drugs from different therapeutic groups, which very often interact and intensify comorbidities, sometimes unrelated mechanisms. Sufficient awareness of potential drug interactions is critical in clinical practice, as it allows both to avoid disruption of proper pharmacotherapy and achieve substantive results. Therefore, this review aims to analyze the interactions of antidepressants with other concomitant medications. Against the backdrop of experimental research and a thorough analysis of the up-to-date literature, the authors discuss in detail the mechanisms and effects of action of individual drug interactions and adaptogens, including the latest antidepressants.

Pregnane X Receptor (PXR) Polymorphisms and Cancer Treatment

Pregnane X Receptor (PXR) belongs to the nuclear receptors' superfamily and mainly functions as a xenobiotic sensor activated by a variety of ligands. PXR is widely expressed in normal and malignant tissues. Drug metabolizing enzymes and transporters are also under PXR's regulation. Antineoplastic agents are of particular interest since cancer patients are characterized by significant intra-variability to treatment response and severe toxicities. Various PXR polymorphisms may alter the function of the protein and are linked with significant effects on the pharmacokinetics of chemotherapeutic agents and clinical outcome variability. The purpose of this review is to summarize the roles of PXR polymorphisms in the metabolism and pharmacokinetics of chemotherapeutic drugs. It is also expected that this review will highlight the importance of PXR polymorphisms in selection of chemotherapy, prediction of adverse effects and personalized medicine.

Determination of benchmark doses for linear furanocoumarin consumption associated with inhibition of cytochrome P450 1A2 isoenzyme activity in healthy human adults

Millions of individuals globally consume traditional herbal medicines (THMs), which contain abundant amounts of linear furanocoumarins. Linear furanocoumarins (i.e., 8-methoxypsoralen, 5-methoxypsoralen, and isopimpinellin) are inhibitors of cytochrome P450 (CYP) isoenzymes including 1A2, a major enzyme involved in drug metabolism and carcinogen bioactivation. Despite the high consumption of furanocoumarin-containing THMs, no studies have measured the furanocoumarin consumption level that triggers an inhibition to CYP1A2 activity in humans. The first objective was to verify if the potencies of the three furanocoumarins are additive towards the inhibition of CYP1A2 activity in vitro using concentration-addition and whole-mixture chemical-mixture-assessment models. A second objective was to determine the benchmark dose (BMD) with the mixtures of furanocoumarin oral doses, expressed as 8-MOP equivalents, and to assess the in vivo CYP1A2 activity, expressed as inhibition percentages. The in vitro results indicated that the three furanocoumarin inhibitory potencies were additive in the THM extracts, validating the use of the concentration-addition model in total furanocoumarin dose-equivalent calculations. Using the USEPA BMD software, the BMD was 18.9 μg 8-MOP equivalent/kg body weight. This information is crucial for furanocoumarin-related health-assessment studies and the regulation of THMs. Further studies should be performed for the remaining major metabolic enzymes to complete the safety profile of furanocoumarin-containing THMs and to provide accurate warning labelling.

Current Role of Herbal and Natural Preparations

Depression remains difficult to manage, despite the many registered treatments available. For many depressed individuals, particularly those who have not responded to and/or had adverse effects from standard therapies, herbal and natural medications represent a potentially valuable alternative. This chapter will review several natural remedies used in the treatment of depression. Specific remedies covered include St. John's wort (SJW), S-adenosyl-L-methionine (SAMe), omega-3 fatty acids, rhodiola, and others. We will begin by providing some historical and social context about these remedies. Then we will review efficacy and safety data, as well as biological mechanisms of action of these therapies. Finally, we will discuss the limitations of the current state of knowledge and provide suggestions for a productive research agenda focused on natural remedies. While many questions about these treatments remain unanswered and much work needs to be done before we determine their place in the psychiatric armamentarium, we believe that this chapter will give psychiatrists a good perspective on the pros and cons of herbal and natural antidepressants as part of the pharmacological armamentarium and sensible guidelines on how and when they should be used.

Development of in Silico Models for Predicting P-Glycoprotein Inhibitors Based on a Two-Step Approach for Feature Selection and Its Application to Chinese Herbal Medicine Screening

P-glycoprotein (P-gp) is regarded as an important factor in determining the ADMET (absorption, distribution, metabolism, elimination, and toxicity) characteristics of drugs and drug candidates. Successful prediction of P-gp inhibitors can thus lead to an improved understanding of the underlying mechanisms of both changes in the pharmacokinetics of drugs and drug-drug interactions. Therefore, there has been considerable interest in the development of in silico modeling of P-gp inhibitors in recent years. Considering that a large number of molecular descriptors are used to characterize diverse structural moleculars, efficient feature selection methods are required to extract the most informative predictors. In this work, we constructed an extensive available data set of 2428 molecules that includes 1518 P-gp inhibitors and 910 P-gp noninhibitors from multiple resources. Importantly, a two-step feature selection approach based on a genetic algorithm and a greedy forward-searching algorithm was employed to select the minimum set of the most informative descriptors that contribute to the prediction of P-gp inhibitors. To determine the best machine learning algorithm, 18 classifiers coupled with the feature selection method were compared. The top three best-performing models (flexible discriminant analysis, support vector machine, and random forest) and their ensemble model using respectively only 3, 9, 7, and 14 descriptors achieve an overall accuracy of 83.2%-86.7% for the training set containing 1040 compounds, an overall accuracy of 82.3%-85.5% for the test set containing 1039 compounds, and a prediction accuracy of 77.4%-79.9% for the external validation set containing 349 compounds. The models were further extensively validated by DrugBank database (1890 compounds). The proposed models are competitive with and in some cases better than other published models in terms of prediction accuracy and minimum number of descriptors. Applicability domain then was addressed by developing an ensemble classification model to obtain more reliable predictions. Finally, we employed these models as a virtual screening tool for identifying potential P-gp inhibitors in Traditional Chinese Medicine Systems Pharmacology (TCMSP) database containing a total of 13 051 unique compounds from 498 herbs, resulting in 875 potential P-gp inhibitors and 15 inhibitor-rich herbs. These predictions were partly supported by a literature search and are valuable not only to develop novel P-gp inhibitors from TCM in the early stages of drug development, but also to optimize the use of herbal remedies.

Pharmacogenomics and herb-drug interactions: merge of future and tradition

The worldwide using of herb products and the increasing potential herb-drug interaction issue has raised enthusiasm on discovering the underlying mechanisms. Previous review indicated that the interactions may be mediated by metabolism enzymes and transporters in pharmacokinetic pathways. On the other hand, an increasing number of studies found that genetic variations showed some influence on herb-drug interaction effects whereas these genetic factors did not draw much attention in history. We highlight that pharmacogenomics may involve the pharmacokinetic or pharmacodynamic pathways to affect herb-drug interaction. We are here to make an updated review focused on some common herb-drug interactions in association with genetic variations, with the aim to help safe use of herbal medicines in different individuals in the clinic.

Role of pregnane X receptor in chemotherapeutic treatment

Pregnane X receptor (PXR) is a member of the nuclear receptor superfamily that differently expresses not only in human normal tissues but also in numerous types of human cancers. PXR can be activated by many endogenous substances and exogenous chemicals, and thus affects chemotherapeutic effects and intervenes drug-drug interactions by regulating its target genes involving drug metabolism and transportation, cell proliferation and apoptosis, and modulating endobiotic homeostasis. Tissue and context-specific regulation of PXR contributes to diverse effects in the treatment for numerous cancers. Genetic variants of PXR lead to intra- and inter-individual differences in the expression and inducibility of PXR, resulting in different responses to chemotherapy in PXR-positive cancers. The purpose of this review is to summarize and discuss the role of PXR in the metabolism and clearance of anticancer drugs. It is also expected that this review will provide insights into PXR-mediated enhancement for chemotherapeutic treatment, prediction of drug-drug interactions and personalized medicine.

Herb-drug interaction prediction based on the high specific inhibition of andrographolide derivatives towards UDP-glucuronosyltransferase (UGT) 2B7

Herb-drug interaction strongly limits the clinical application of herbs and drugs, and the inhibition of herbal components towards important drug-metabolizing enzymes (DMEs) has been regarded as one of the most important reasons. The present study aims to investigate the inhibition potential of andrographolide derivatives towards one of the most important phase II DMEs UDP-glucuronosyltransferases (UGTs). Recombinant UGT isoforms (except UGT1A4)-catalyzed 4-methylumbelliferone (4-MU) glucuronidation reaction and UGT1A4-catalyzed trifluoperazine (TFP) glucuronidation were employed to firstly screen the andrographolide derivatives' inhibition potential. High specific inhibition of andrographolide derivatives towards UGT2B7 was observed. The inhibition type and parameters (Ki) were determined for the compounds exhibiting strong inhibition capability towards UGT2B7, and human liver microsome (HLMs)-catalyzed zidovudine (AZT) glucuronidation probe reaction was used to furtherly confirm the inhibition behavior. In combination of inhibition parameters (Ki) and in vivo concentration of andrographolide and dehydroandrographolide, the potential in vivo inhibition magnitude was predicted. Additionally, both the in vitro inhibition data and computational modeling results provide important information for the modification of andrographolide derivatives as selective inhibitors of UGT2B7. Taken together, data obtained from the present study indicated the potential herb-drug interaction between Andrographis paniculata and the drugs mainly undergoing UGT2B7-catalyzed metabolic elimination, and the andrographolide derivatives as potential candidates for the selective inhibitors of UGT2B7.

The classification and application of toxic Chinese materia medica

Many important drugs in the Chinese materia medica (CMM) are known to be toxic, and it has long been recognized in classical Chinese medical theory that toxicity can arise directly from the components of a single CMM or may be induced by an interaction between combined CMM. Traditional Chinese Medicine presents a unique set of pharmaceutical theories that include particular methods for processing, combining and decocting, and these techniques contribute to reducing toxicity as well as enhancing efficacy. The current classification of toxic CMM drugs, traditional methods for processing toxic CMM and the prohibited use of certain combinations, is based on traditional experience and ancient texts and monographs, but accumulating evidence increasingly supports their use to eliminate or reduce toxicity. Modern methods are now being used to evaluate the safety of CMM; however, a new system for describing the toxicity of Chinese herbal medicines may need to be established to take into account those herbs whose toxicity is delayed or otherwise hidden, and which have not been incorporated into the traditional classification. This review explains the existing classification and justifies it where appropriate, using experimental results often originally published in Chinese and previously not available outside China.