The role of P-glycoprotein in CNS antihistamine effects

Comparison of new secondgeneration H1 receptor blockers with some molecules; a study involving DFT, molecular docking, ADMET, biological target and activity

Although the antiallergic properties of compounds such as CAPE, Melatonin, Curcumin, and Vitamin C have been poorly discussed by experimental studies, the antiallergic properties of these famous molecules have never been discussed with calculations. The histamine-1 receptor (H1R) belongs to the family of rhodopsin-like G-protein-coupled receptors expressed in cells that mediate allergies and other pathophysiological diseases. In this study, pharmacological activities of FDA-approved second generation H1 antihistamines (Levocetirizine, desloratadine and fexofenadine) and molecules such as CAPE, Melatonin, Curcumin, Vitamin C, ADMET (Absorption, Distribution, Metabolism, Excretion, Toxicity) profiles, density functional theory (DFT), molecular docking, biological targets and activities were compared by calculating. Since drug development is an extremely risky, costly and time-consuming process, the data obtained in this study will facilitate and guide future studies. It will also enable researchers to focus on the most promising compounds, providing an effective design strategy. Their pharmacological activity was carried out using computer-based computational techniques including DFT, molecular docking, ADMET analysis, biological targeting, and activity methods. The best binding sites of Desloratadine, Levocetirizine, Fexofenadine, CAPE, Quercetin, Melatonin, curcumin, Vitamin C ligands to Desmoglein 1, Human Histamine H1 receptor, IgE and IL13 protons were determined by molecular docking method and binding energy and interaction states were analyzed. Fexofenadine and Quercetin ligand showed the most effective binding affinity. Melatonin had the best Caco-2 permeability PPB values of Quercetin, CAPE and Curcumin were at optimal levels. On the OATP1B1 and OATP1B3 of curcumin and CAPE, Quercetin was found to have strong inhibition effects on BCRP. Melatonin and CAPE were found to have the highest inhibition values on CYP1A2, while CAPE had the highest inhibition values on CYP2C19 and CYP2C9. Vitamin C and Quercetin were found to be safer in terms of cardiac toxicity and mutagenic risks, while Desloratadine and Levocetirizine carried high risks of neurotoxicity and hematotoxicity, while CAPE was noted for its high enzyme inhibitory activities and low toxicity profiles, while the hERG blockade, DILI, and cytotoxicity values of other compounds pointed to various safety concerns. This study demonstrated the potential of machine learning methods in understanding and discovering H1 receptor blockers. The results obtained provide important clues in the development of important strategies in the clinical use of H1 receptor blockers. In the light of these data, CAPE and Quercetin are remarkable molecules.

Classics in Chemical Neuroscience: Deliriant Antihistaminic Drugs

Antihistaminic drugs are widely used clinically and have long been primarily known for their use to treat severe allergic conditions caused by histamine release. Antihistaminic drugs also exert central nervous system (CNS) effects, acting as anxiolytics, hypnotics, and neuroleptics. However, these drugs also have multiple serious neuropharmacological side-effects, inducing delirium, hyperarousal, disorganized behavior, and hallucinations. Due to their robust CNS effects, antihistamines are also increasingly abused, with occasional overdoses and life-threatening toxicity. Here, we discuss chemical and neuropharmacological aspects of antihistaminic drugs in both human and animal (experimental) models and outline their current societal and mental health importance as neuroactive substances.

Factors Associated with Acute Injurious Falls in Elderly Hospitalized Patients: A Multicenter Descriptive Study

BACKGROUND

The Centers for Medicare & Medicaid Services Hospital-Acquired Conditions (CMS-HAC) links Medicare payments to health care quality. Experiencing a serious disability or death associated with a fall in a health care facility based on diagnosis codes has been identified as an opportunity for improvement. Multiple factors contribute to an inpatient fall, including medications that affect cognition in older adults. The primary aim of this study was to investigate the effect of the commonly prescribed classes of medications on the CMS-HAC falls and trauma definition in US hospitals in a large inpatient database from 2019 to 2021.

METHODS

The authors analyzed data from 835 hospitals in the Vizient Clinical Data Base between January 1, 2019, and December 31, 2021, on patients ≥ 65 years of age with CMS-HAC patient falls and trauma codes. Using logistic regression and stepwise Poisson regression analysis, the authors identified demographic, clinical, and hospital-related variables associated with falls meeting the CMS-HAC definition. The top 20 prescribed drug classes in these patients were also identified.

RESULTS

Among 11,064,024 patient encounters, 5,978 met the CMS-HAC definition of a serious fall. Patients who experienced a serious fall were significantly more likely to be > 79 years of age (p < 0.001, odds ratio [OR] 1.30, 95% confidence interval [CI] 1.23-1.37), have a history of prior falls (p < 0.001, OR 2.30, 95% CI 2.11-2.50), have a code for dementia (p < 0.001, OR 1.50, 95% CI 1.40-1.60), and have higher anticholinergic cognitive burden (ACB) scores (p < 0.001, OR 1.14, 95% CI 1.13-1.14). Specific medication classes associated with CMS-HAC falls were first-generation antihistamines (p < 0.00, OR 1.21, 95% CI 1.09-1.35), second-generation antihistamines (p ≤ 0.001, OR 1.15, 95% CI 1.13-1.19), and atypical antipsychotics (p < 0.001, OR 1.18, CI 1.13-1.29).

CONCLUSION

Patients who experience a fall meeting the CMS-HAC fall definition are significantly more likely to have a prior history of falling, dementia, and a higher ACB score. Results from this study may inform future quality improvement work aimed at reducing injurious falls.

Transporter-Mediated Drug Delivery

Transmembrane transport of small organic and inorganic molecules is one of the cornerstones of cellular metabolism. Among transmembrane transporters, solute carrier (SLC) proteins form the largest, albeit very diverse, superfamily with over 400 members. It was recognized early on that xenobiotics can directly interact with SLCs and that this interaction can fundamentally determine their efficacy, including bioavailability and intertissue distribution. Apart from the well-established prodrug strategy, the chemical ligation of transporter substrates to nanoparticles of various chemical compositions has recently been used as a means to enhance their targeting and absorption. In this review, we summarize efforts in drug design exploiting interactions with specific SLC transporters to optimize their therapeutic effects. Furthermore, we describe current and future challenges as well as new directions for the advanced development of therapeutics that target SLC transporters.

Pharmacogenomics for the efficacy and side effects of antihistamines

Antihistamines, especially H1 antihistamines, are widely used in the treatment of allergic diseases such as urticaria and allergic rhinitis, mainly for reversing elevated histamine and anti-allergic effects. Antihistamines are generally safe, but some patients experience adverse reactions, such as cardiotoxicity, central inhibition, and anticholinergic effects. There are also individual differences in antihistamine efficacy in clinical practice. The concept of individualized medicine has been deeply rooted in people's minds since it was put forward. Pharmacogenomics is the study of the role of inheritance in individual variations in drug response. In recent decades, pharmacogenomics has been developing rapidly, which provides new ideas for individualized medicine. Polymorphisms in the genes encoding metabolic enzymes, transporters, and target receptors have been shown to affect the efficacy of antihistamines. In addition, recent evidence suggests that gene polymorphisms influence urticaria susceptibility and antihistamine therapy. Here, we summarize current reports in this area, aiming to contribute to future research in antihistamines and clinical guidance for antihistamines use in individualized medicine.

Bilastine 10 and 20 mg in paediatric and adult patients: an updated practical approach to treatment decisions

Background

Bilastine, a non-sedating H₁-antihistamine, is indicated to treat the symptoms of allergic disorders (e.g. rhinoconjunctivitis and urticaria) in adults and adolescents and, more recently, in children. Following its marketing approval, many questions regarding the ideal use of bilastine in various clinical practice situations have been received by the Medical Information Department (MID) of Faes Farma Spain. This article is an update of a previous review, with a focus on recent clinical information on the use of bilastine in paediatric and other populations.

Methods

Results of recent clinical studies in paediatric and other populations as well as questions received and responses provided by the Faes Farma MID.

Results

The information regarding the use of bilastine in paediatric patients is the most relevant aspect of this updated review. The stepwise approval of the paediatric formulations in various countries started with the European Medicines Agency approval in 2017 in accordance with a 2009 Paediatric Investigation Plan, followed by approval in other countries. The queries that are most commonly received by the Faes Farma MID include the potential for drug interactions involving bilastine and other frequently used drugs, and the use of bilastine in special populations or to treat specific symptoms related to allergic conditions. As the concomitant use of many medications is not permitted during clinical trials, the advice provided regarding the concomitant use of other medications with bilastine considers the pharmacological properties of both the drug in question and bilastine, as well as expert opinion. Likewise, advice regarding the use of bilastine in special populations (e.g. patients with renal impairment, obesity, lactose intolerance, and elderly or pregnant individuals) or to treat specific symptoms (e.g. treatment-resistant urticaria, pruritus or BASCULE syndrome) considers the best evidence from a variety of sources, including clinical studies, real-world experience, guideline recommendations and expert opinion.

Conclusion

This updated review provides current data regarding the best use of bilastine in specific situations and patients and identifies areas in which further knowledge is required. Although decisions regarding the use of bilastine may be aided by expert opinion that relies on knowledge of the underlying science, additional research and evidence are required to answer certain queries regarding the use of bilastine.

Quantum chemical calculation and binding modes of H1R; a combined study of molecular docking and DFT for suggesting therapeutically potent H1R antagonist

Histamine-1 receptor (H1R) belongs to the family of rhodopsin-like G-protein-coupled receptors expressed in cells that mediates allergies and other pathophysiological diseases. For alleviation of allergic symptoms, H1R antagonists are therapeutic drugs; of which the most frequently prescribed are second generation drugs, such as; Cetirizine, Loratadine, Hydroxyzine, Desloratadine, Bepotastine, Acrivastine and Rupatadine. To understand their potency, binding affinity and interaction; we have employed molecular docking and quantum chemical study such as; Induced-fit docking and calculation of quantum chemical descriptors. This study also introduces the binding site characterization of H1R, with its known antagonists and Curcumin (our proposed alternative H1R antagonist); useful for future drug target site. The interactive binding site residues of H1R are found to be; Lys-191, Tyr-108, Asp-107, Tyr-100, Lys-179, Lys-191, Thr-194, Trp-428, Phe-432, Tyr-458, Hie-450, with most of these shown to be inhibited by naturally-occurring compound curcumin. Amongst the FDA approved drugs, Hydroxyzine showed best ligand binding affinity, calculated as - 141.491 kcal/mol and naturally occurring compound, Curcumin showed binding affinity of - 87.046 kcal/mol. The known antagonists of H1R has been used for hypothesizing curcumin as naturally occurring lead compound for the target using accurate molecular docking simulation study. Though the pharmacological action of known inhibitor is already established, they could differ from their reactivity, which we have also focused in our study for predicting drug reactivity.

Modafinil enhances alerting-related brain activity in attention networks

RATIONALE

Modafinil is a wake-promoting agent and has been reported to be effective in improving attention in patients with attentional disturbance. However, neural substrates underlying the modafinil effects on attention are not fully understood.

OBJECTIVES

We employed a functional magnetic resonance imaging (fMRI) study with the attention network test (ANT) task in healthy adults and examined which networks of attention are mainly affected by modafinil and which neural substrates are responsible for the drug effects.

METHODS

We used a randomized placebo-controlled within-subjects cross-over design. Twenty-three healthy adults participated in two series of an fMRI study, taking either a placebo or modafinil. The participants performed the ANT task, which is designed to measure three distinct attentional networks, alerting, orienting, and executive control, during the fMRI scanning. The effects of modafinil on behavioral performance and regional brain activity were analyzed.

RESULTS

We found that modafinil enhanced alerting performance and showed greater alerting network activity in the left middle and inferior occipital gyri as compared with the placebo. The brain activations in the occipital regions were positively correlated with alerting performance.

CONCLUSIONS

Modafinil enhanced alerting performance and increased activation in the occipital lobe in the alerting network possibly relevant to noradrenergic activity during the ANT task. The present study may provide a rationale for the treatment of patients with distinct symptoms of impaired attention.

Clinical Implications of P-Glycoprotein Modulation in Drug-Drug Interactions

Drug-drug interactions (DDIs) occur commonly and may lead to severe adverse drug reactions if not handled appropriately. Considerable information to support clinical decision making regarding potential DDIs is available in the literature and through various systems providing electronic decision support for healthcare providers. The challenge for the prescribing physician lies in sorting out the evidence and identifying those drugs for which potential interactions are likely to become clinically manifest. P-glycoprotein (P-gp) is a drug transporting protein that is found in the plasma membranes in cells of barrier and elimination organs, and plays a role in drug absorption and excretion. Increasingly, P-gp has been acknowledged as an important player in potential DDIs and a growing body of information on the role of this transporter in DDIs has become available from research and from the drug approval process. This has led to a clear need for a comprehensive review of P-gp-mediated DDIs with a focus on highlighting the drugs that are likely to lead to clinically relevant DDIs. The objective of this review is to provide information for identifying and interpreting evidence of P-gp-mediated DDIs and to suggest a classification for individual drugs based on both in vitro and in vivo evidence (substrates, inhibitors and inducers). Further, various ways of handling potential DDIs in clinical practice are described and exemplified in relation to drugs interfering with P-gp.

The clinical pharmacology of non-sedating antihistamines

We previously reported on brain H₁ receptor occupancy measurements of antihistamines in human brain using [¹¹C]doxepin and positron emission tomography (PET). We proposed the use of brain H₁ receptor occupancy to classify antihistamines objectively into three categories of sedating, less-sedating, and non-sedating antihistamines according to their sedative effects. Non-sedating antihistamines are recommended for the treatment of allergies such as pollinosis and atopic dermatitis because of their low penetration into the central nervous system. Physicians and pharmacists are responsible for fully educating patients about the risks of sedating antihistamines from pharmacological points of view. If a sedating antihistamine must be prescribed, its sedative effects should be thoroughly considered before choosing the drug. Non-sedating antihistamines should be preferentially used whenever possible as most antihistamines are equally efficacious, while adverse effects of sedating antihistamines can be serious. This review summarizes the pharmacological properties of clinically useful non-sedating antihistamines from the perspective of histamine function in the CNS.

Turmeric (Curcuma longa) attenuates food allergy symptoms by regulating type 1/type 2 helper T cells (Th1/Th2) balance in a mouse model of food allergy

ETHNOPHARMACOLOGICAL RELEVANCE

Turmeric (Curcuma longa) has traditionally been used to treat pain, fever, allergic and inflammatory diseases such as bronchitis, arthritis, and dermatitis. In particular, turmeric and its active component, curcumin, were effective in ameliorating immune disorders including allergies. However, the effects of turmeric and curcumin have not yet been tested on food allergies.

MATERIALS AND METHODS

Mice were immunized with intraperitoneal ovalbumin (OVA) and alum. The mice were orally challenged with 50mg OVA, and treated with turmeric extract (100mg/kg), curcumin (3mg/kg or 30 mg/kg) for 16 days. Food allergy symptoms including decreased rectal temperature, diarrhea, and anaphylaxis were evaluated. In addition, cytokines, immunoglobulins, and mouse mast cell protease-1 (mMCP-1) were evaluated using ELISA.

RESULTS

Turmeric significantly attenuated food allergy symptoms (decreased rectal temperature and anaphylactic response) induced by OVA, but curcumin showed weak improvement. Turmeric also inhibited IgE, IgG1, and mMCP-1 levels increased by OVA. Turmeric reduced type 2 helper cell (Th2)-related cytokines and enhanced a Th1-related cytokine. Turmeric ameliorated OVA-induced food allergy by maintaining Th1/Th2 balance. Furthermore, turmeric was confirmed anti-allergic effect through promoting Th1 responses on Th2-dominant immune responses in immunized mice.

CONCLUSION

Turmeric significantly ameliorated food allergic symptoms in a mouse model of food allergy. The turmeric as an anti-allergic agent showed immune regulatory effects through maintaining Th1/Th2 immune balance, whereas curcumin appeared immune suppressive effects. Therefore, we suggest that administration of turmeric including various components may be useful to ameliorate Th2-mediated allergic disorders such as food allergy, atopic dermatitis, and asthma.

Bilastine: a new antihistamine with an optimal benefit-to-risk ratio for safety during driving

INTRODUCTION

Rational selection of a second-generation H1-antihistamine requires efficacy and safety considerations, particularly regarding central nervous system (CNS) effects (cognitive and psychomotor function), potential for driving impairment, minimal sedative effects and a lack of interactions. This review evaluates the key safety features of the non-sedating antihistamine, bilastine, during driving and in preventing road traffic accidents.

AREAS COVERED

Among the second-generation H1-antihistamines, sedative effects which can affect cognitive and psychomotor performance, and possibly driving ability, may not be similar. Bilastine is absorbed rapidly, undergoes no hepatic metabolism or cytochrome P450 interaction (minimal drug-drug interaction potential), and is a substrate for P-glycoprotein (limiting CNS entry). Positron emission tomography showed that, compared with other second-generation H1-antihistamines, bilastine has the lowest cerebral histamine H1-receptor occupancy. Bilastine 20 mg once daily (therapeutic dose) is non-sedating, does not enhance the effects of alcohol or CNS sedatives, does not impair driving performance and has at least similar efficacy as other second-generation H1-antihistamines in the treatment of allergic rhinoconjunctivitis and urticaria.

EXPERT OPINION

Current evidence shows that bilastine has an optimal benefit-to-risk ratio, meeting all conditions for contributing to safety in drivers who need antihistamines, and hence for being considered as an antihistamine of choice for drivers.

A method to predict different mechanisms for blood-brain barrier permeability of CNS activity compounds in Chinese herbs using support vector machine

The blood-brain barrier (BBB), a highly selective barrier between central nervous system (CNS) and the blood stream, restricts and regulates the penetration of compounds from the blood into the brain. Drugs that affect the CNS interact with the BBB prior to their target site, so the prediction research on BBB permeability is a fundamental and significant research direction in neuropharmacology. In this study, we combed through the available data and then with the help of support vector machine (SVM), we established an experiment process for discovering potential CNS compounds and investigating the mechanisms of BBB permeability of them to advance the research in this field four types of prediction models, referring to CNS activity, BBB permeability, passive diffusion and efflux transport, were obtained in the experiment process. The first two models were used to discover compounds which may have CNS activity and also cross the BBB at the same time; the latter two were used to elucidate the mechanism of BBB permeability of those compounds. Three optimization parameter methods, Grid Search, Genetic Algorithm (GA), and Particle Swarm Optimization (PSO), were used to optimize the SVM models. Then, four optimal models were selected with excellent evaluation indexes (the accuracy, sensitivity and specificity of each model were all above 85%). Furthermore, discrimination models were utilized to study the BBB properties of the known CNS activity compounds in Chinese herbs and this may guide the CNS drug development. With the relatively systematic and quick approach, the application rationality of traditional Chinese medicines for treating nervous system disease in the clinical practice will be improved.

Why are second-generation H1-antihistamines minimally sedating?

H1-antihistamines are widely used in treating allergic disorders, e.g., conjunctivitis, urticaria, dermatitis and asthma. The first-generation H1-antihistamines have a much greater sedative effect than the second-generation H1-antihistamines. Researchers could not offer a satisfactory explanations until late 1990s when studies showed that second-generation H1-antihistamines were substrates of P-glycoprotein. P-glycoprotein, expressed in the blood-brain barrier, acts as an efflux pump to decrease the concentration of H1-antihistamines in the brain, which minimizes drug effects on the central nervous system and results in less sedation. P-glycoprotein is found in the apical side of the epithelium. It consists of transmembrane domains that bind substrates/drugs and nucleotide-binding domains that bind and hydrolyze ATP to generate energy for the drug efflux. This review mainly discusses interactions between P-glycoprotein and commonly used second-generation H1-antihistamines. In addition, it describes other possible determining factors of minimal sedating properties of second-generation H1-antihistamines.