Therapeutic potential of histamine H4 receptor antagonist as a preventive treatment for diabetic retinopathy in mice.

Diabetic retinopathy (DR) is a prevalent complication of diabetes, often resulting in vision loss and blindness. Existing treatments primarily aim to control blood sugar levels and inhibit angiogenesis. However, current therapies for DR, such as anti-VEGF and laser photocoagulation, are frequently invasive, and can cause adverse side effects. Consequently, there is a critical need for new preventive therapeutics to address DR more effectively. This study aimed to examine the therapeutic potential of a histamine H4 receptor (HRH4) antagonist as a preventive treatment for DR in mice. A mouse model of DR was established by intraperitoneally injecting 200 mg/kg of streptozotocin (STZ). Immune cell infiltration into the retina of mice with STZ-induced diabetes was measured using fluorescence-activated cell sorting (FACS) 12 weeks after STZ injection. The preventive effects of the HRH4 antagonist on inflammation and pathological retinal vessel leakage were determined in a mouse model of DR. Infiltration of HRH4-expressing macrophages increased in the retina of mice with STZ-induced DR. The HRH4 antagonist prevented macrophage infiltration and retinal vascular leakage to prevent STZ-induced DR in mice without causing any retinal toxicity. The infiltration of macrophages increased in the retina of mice with STZ-induced diabetes through HRH4, indicating that HRH4 is potentially a novel preventative therapeutic target in DR. These findings suggest that targeting HRH4 is a promising strategy for the prevention and treatment of DR.

Derivatization-free sustainable spectrofluorimetric estimation of antihistamine drug mizolastine in pharmaceutical and biological matrices.

Mizolastine is an antihistamine drug that is commonly used for treatment of chronic urticaria and allergic rhinitis. In this study, a facile, rapid, and sustainable fluorimetric method was established for the estimation of mizolastine in pharmaceutical and biological matrices for the first time. The approach methodology relied on the direct assessment of mizolastine's intrinsic fluorescence at 313 nm after excitation at 272 nm. This intrinsic fluorescence, stemming from the benzimidazole fluorophore moiety in mizolastine structure, serves as a distinctive marker for its precise quantification in the spiked human plasma and pharmaceutical formulations with high %recovery. The method exhibits reasonable sensitivity with lower limits of detection and quantification of 5.4 and 16.6 ng mL-1, respectively, across a concentration range of 25.0-2000.0 and 50-1000 ng mL-1 for the standard mizolastine analysis and mizolastine assay in the plasma sample, respectively. Moreover, the established method was applied to assess tablet content uniformity and mizolastine assay in plasma samples with high recoveries (98.50%-100.20%). Such applications underscore the method's potential applicability within quality control laboratories, preventing the need for sample preparation or laborious extraction steps. Finally, the method's sustainability and practicality were confirmed by applying different greenness and whiteness metrics, yielding excellent results.

From Research to Practice: The Latest Data on Evolving Treatments for Chronic Spontaneous Urticaria.

Chronic spontaneous urticaria (CSU) should be on every dermatology practitioner's radar. CSU is a skin disorder marked by wheals, angioedema, or both for more than 6 weeks. Patients with CSU experience unexplained, itchy wheals that appear and disappear, traveling around the body and lasting less than 24 hours per area. Angioedema accompanies wheals for up to 48 hours in around half of cases. CSU is a diagnosis of exclusion, relying heavily on patient history to differentiate CSU symptoms from other causes of urticaria or angioedema. But reassuringly, CSU has a simple diagnostic algorithm and a clear initial treatment path. First-line strategies include non-pharmacologic approaches, and second-generation antihistamines (2gAH) administered up to 4 times their standard dose. Omalizumab and cyclosporine (off-label) are second- and third-line options, respectively. However, many patients will continue to have CSU symptoms despite consistent maximum-dose treatment. Novel therapies, including biologic agents and small molecule drugs targeting mast cell activation and inflammatory mediators, show promise in treating CSU refractory to standard therapy. However, further research is needed to establish their efficacy and safety in clinical practice. J Drugs Dermatol. 2024;23:9(Suppl 2):s5-14.Access the CME Activity.

Epidemiological and clinical characteristics of adult patients with chronic spontaneous urticaria in Latvia: insights from a two-centre study.

Chronic spontaneous urticaria (CSU) significantly impacts the quality of life of affected individuals. This study aimed to elucidate the epidemiological and clinical profiles of adult CSU patients in Latvia. Patient interviews and electronic medical records from two study centres in Riga, Latvia, were reviewed. PROMs, including UCT, UAS7, USS, and CU-Q2oL, were used to assess disease control, activity, severity, and quality of life. Statistical analysis was performed using Jamovi v. 2.3.28 and IBM SPSS v. 29.0.0.0. The cohort included 140 CSU patients (76.4% female; mean age 41.3 ± 14.9 years), mostly urban residents (87.1%) and non-smokers (53.6%). Urticaria with angioedema occurred in 52.1% and isolated urticaria in 47.9%, with 40% experiencing CSU for 1-5 years. Accompanying symptoms were reported by 63% and triggers by 72.9%. Allergy history and autoimmune disease diagnosis were noted in 49.3% and 29.3%. Treatment mainly involved second-generation antihistamines (85.7%) and omalizumab (17.9%). Mean scores for USS, UCT, and UAS7 were 28.8 (SD: 17.8), 8.2 (SD: 3.7), and 17.2 (SD: 14.1). UAS7 indicated severe CSU in 28.6%, and UCT suggested poorly controlled disease in 77.9%. CU-Q2oL total scores revealed mental status as the most affected domain (mean score: 51.7, SD: 28.7), with a significant association between accompanying symptoms and questionnaire scores. This study provides insights into the demographic and clinical aspects of CSU patients in Latvia, highlighting areas for potential improvement in patient care and emphasizing the need for further investigation into treatment outcomes and patient quality of life.

[Modern approaches to rational combination pharmacotherapy of allergic rhinitis]. / Sovremennye podkhody k ratsional'noi kombinirovannoi farmakoterapii allergicheskogo rinita.

Allergic rhinitis (AR) can significantly reduce the quality of life of patients leading to increased fatigue, mood changes, cognitive impairment, and depression. In clinical practice, insufficient effectiveness of initial AR monotherapy is often noted, and a significant proportion of patients referring for medical care have moderate-severe AR. In this regard, the issues of optimization of combined pharmacological treatment of AR are becoming more and more urgent. This paper provides analysis of the opportunities of combined pharmacotherapy within the framework of current management strategy of AR. Based on the results of some studies and known pharmacological properties of medications it is being discussed the advantages of combined use of intranasal corticosteroids and leukotriene receptor antagonists, in particular mometasone furoate and montelukast, in the therapy of AR, including such comorbidities as bronchial asthma, chronic polyposis rhinosinusitis and pharyngeal tonsil hyperplasia. Some aspects of combination therapy with montelukast and second-generation systemic antihistamines as an alternative approach in case of inability to take intranasal corticosteroids, including the reasonability of using a fixed combination of montelukast and levocetirizine, are analyzed from the perspective of rational pharmacotherapy. The problem of interchangeability of brand-name and generic drugs for the treatment of AR is discussed, considering the almost complete absence of studies of their therapeutic equivalence.

Combining dipyridamole and cilostazol with up-dosing antihistamines improves outcomes in chronic spontaneous urticaria with high D-dimer levels: A randomized controlled trial.

In a double-blind, randomized controlled trial, we investigated the effectiveness of adding antiplatelet drugs to up-dosing antihistamines for the treatment of chronic spontaneous urticaria (CSU) in patients with elevated D-dimer levels who had an inadequate response to conventional antihistamine doses. Twenty patients with Urticaria Activity Score over 7 days (UAS7) ≥16 and D-dimer >500 ng/mL were randomized to receive either antiplatelet therapy (cilostazol 150 mg/day + dipyridamole 50 mg/day) with antihistamine (desloratadine 20 mg/day) or antihistamine alone for 4 weeks. The antiplatelet group demonstrated a greater decrease in UAS7 compared to the control group (28.10 to 8.90 vs. 22.90 to 16.40, p < 0.001 vs. p = 0.054). Both groups experienced improved quality of life (DLQI), but the improvement was greater in the antiplatelet group (p = 0.046). D-dimer levels decreased only in the antiplatelet group (1133.67 ng/mL to 581.89 ng/mL, p = 0.013) with no significant change observed in the control group. This suggests that combining dipyridamole and cilostazol with up-dosing antihistamines may be more effective for CSU patients with high D-dimer levels compared to up-dosing antihistamines alone. This could be due to a reduction in platelet activation, as evidenced by the decrease in D-dimer levels observed in the antiplatelet group.

First-Generation Antihistamines and Seizures in Young Children.

Importance: The widespread use of antihistamines in children for treatment of common cold symptoms and their central nervous system effects, like drowsiness, underscore the importance of being aware of the associated risks. Objective: To assess associations between prescriptions of first-generation antihistamines and seizures in children using a comprehensive and nationwide dataset. Design, Setting, and Participants: This cohort study used a self-controlled case-crossover design. Data were obtained from the National Health Insurance Service database in Korea. Children born between January 1, 2002, and December 31, 2005, who visited the emergency department for seizure events (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, codes R56.8, G40, and G41) during the follow-up period were included. Follow-up was completed on December 31, 2019, and data were analyzed from June 3, 2023, to January 30, 2024. Exposure: First-generation antihistamine prescription. Main Outcomes and Measures: Primary outcome consisted of an index seizure event. Odds ratios (ORs) for seizure events were estimated using a conditional logistic regression model, comparing first-generation antihistamine prescription 1 to 15 days before seizure (hazard period) against control period 1 (31-45 days before the event) and control period 2 (61-75 days before the event) using the same period windows. Stratified analyses were conducted to examine the association with individual participant characteristics. Results: Of 11 729 children who had a seizure event, 3178 (1776 [55.9%] boys) were identified as having been prescribed antihistamines during the hazard or the control period, but not both. Seizure events were predominantly observed in children aged 6 to 24 months (985 [31.0%]) and 25 months to 6 years (1445 [45.5%]). During the hazard period, 1476 first-generation antihistamine prescriptions were recorded, in contrast to 1239 and 1278 prescriptions during control periods 1 and 2, respectively. After multiple confounder adjustments, first-generation antihistamine prescription was associated with an increased seizure event risk during the hazard period (adjusted OR [AOR], 1.22 [95% CI, 1.13-1.31]). Stratified subgroup analyses showed consistent results, particularly in children aged 6 to 24 months who were prescribed first-generation antihistamines having a higher risk (AOR, 1.49 [95% CI, 1.31-1.70]) than children aged 25 months to 6 years (AOR, 1.11 [95% CI, 1.00-1.24]; P = .04 for interaction). Furthermore, sensitivity analyses, including adjustment for exposure window periods, evaluation of new first-generation antihistamine prescriptions, comparison of control points from the same period 1 year prior, and exclusion of individuals using combination drugs, confirmed a similarly high risk. Conclusions and Relevance: In this cohort study, prescriptions for first-generation antihistamines were associated with a 22.0% higher seizure risk in children, especially in those aged 6 to 24 months. These findings emphasize the need for careful and judicious prescription of first-generation antihistamines in young children and underline the need for further research to elucidate associations between antihistamine prescriptions and seizure risk.

A validated stability­indicating reversed­phase­UPLC method for simultaneous estimation of promethazine hydrochloride, methylparaben, propylparaben and sodium benzoate assay of cough suppressant and antihistamine liquid oral dosage forms.

A quick, simple, sensitive, efficient and stability-indicating reverse-phase ultraperformance liquid chromatographic method for the estimation of propylparaben, methylparaben and sodium benzoate in a pharmaceutical liquid oral formulation was developed. A Waters Acquity UPLC BEH C18, 50 × 2.1 mm, 1.7 µm i.d. column was used to perform chromatographic separation with a 0.1% perchloric acid mobile phase used as solvent A and a mixture of 0.1 % perchloric acid and methanol in the ratio 20:80 (v/v), respectively, as solvent B. The experiments were carried out at a flow rate of 0.4 ml/min and the detection wavelength was 240 nm. The compartment temperature of the column was set at 40°C and the injection volume was set at 2 µl. The main aim of the research was to develop a single UPLC assay method for promethazine (active ingredient) and preservatives in the oral solution of promethazine HCl and dextromethorphan HBr that contains promethazine (active ingredient) and methylparaben, propylparaben and sodium benzoate (preservatives). An assay of dextromethorphan HBr was developed and validated by another HPLC method. The drug and preservatives were eluted at retention times of 19.3 min for promethazine HCl, 9.3 min for methylparaben, 18.9 min for propylparaben and 8.9 min for sodium benzoate. Validation of the developed method was carried out as stated by the International Conference on Harmonization guidelines ICH Q2B and under USP<1225>. The analytical parameters verified specificity/selectivity, linearity, accuracy, ruggedness and robustness. The linearity ranges of promethazine HCL, methylparaben, propylparaben and sodium benzoate were 10-100, 10-80, 1.0-8.0 and 10-80 µg/ml, respectively, with a correlation coefficient of active ingredients and preservatives of 1.00. Percentage recoveries of promethazine, propylparaben, methylparaben, and sodium benzoate were 100.0-100.2, 99.0-100.3, 99.5-98.0 and 99.0-100.0%. The validated analytical method proves that the method is specific, precise, linear, accurate, sensitive, rugged and stable, indicating the quantification of the active ingredient and all preservatives in liquid oral formulations.

Pathophysiological role of histamine signaling and its implications in glioblastoma.

Glioblastoma (GBM), an extremely aggressive and prevalent malignant brain tumor, remains a challenge to treat. Despite a multimodality treatment approach, GBM recurrence remains inevitable, particularly with the emergence of temozolomide (TMZ) resistance and limited treatment options. Surprisingly, previous studies show that a history of allergies, atopy, or asthma is inversely associated with GBM risk. Further, the electronic medical record at the University Hospital of Lausanne showed that the GBM patients taking antihistamine during treatment had better survival. Histamine is an essential neurotransmitter in the brain and plays a significant role in regulating sleep, hormonal balance, and cognitive functions. Elevated levels of histamine and increased histamine receptor expression have been found in different tumors and their microenvironments, including GBM. High histamine 1 receptor (HRH1) expression is inversely related to overall and progression-free survival in GBM patients, further emphasizing the role of histamine in disease progression. This review aims to provide insights into the challenges of GBM treatment, the role of histamine in GBM progression, and the rationale for considering antihistamines as targeted therapy. The review concludes by encouraging further investigation into antihistamine mechanisms and their impact on the tumor microenvironment.

Identification of HRH1 as an alternative receptor for SARS-CoV-2: insights from viral inhibition by repurposable antihistamines.

Numerous coreceptors have been shown to facilitate hACE2-dependent or hACE2-independent infection by SARS-CoV-2. A recent study published in mBio by Yu et al. showed that the histamine receptor H1 (HRH1) functions as an alternative receptor for SARS-CoV-2 via direct binding to viral spike proteins (F. Yu, X. Liu, H. Ou, X. Li, et al., mBio e01088-24, 2024, https://doi.org/10.1128/mbio.01088-24). Furthermore, they present compelling evidence that antihistamine drugs targeting HRH1 potently inhibit SARS-CoV-2 entry. This study highlights the therapeutic potential of repurposable antihistamines against COVID-19.

The histamine receptor H1 acts as an alternative receptor for SARS-CoV-2.

Numerous host factors, in addition to human angiotensin-converting enzyme 2 (hACE2), have been identified as coreceptors of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), demonstrating broad viral tropism and diversified druggable potential. We and others have found that antihistamine drugs, particularly histamine receptor H1 (HRH1) antagonists, potently inhibit SARS-CoV-2 infection. In this study, we provided compelling evidence that HRH1 acts as an alternative receptor for SARS-CoV-2 by directly binding to the viral spike protein. HRH1 also synergistically enhanced hACE2-dependent viral entry by interacting with hACE2. Antihistamine drugs effectively prevent viral infection by competitively binding to HRH1, thereby disrupting the interaction between the spike protein and its receptor. Multiple inhibition assays revealed that antihistamine drugs broadly inhibited the infection of various SARS-CoV-2 mutants with an average IC50 of 2.4 µM. The prophylactic function of these drugs was further confirmed by authentic SARS-CoV-2 infection assays and humanized mouse challenge experiments, demonstrating the therapeutic potential of antihistamine drugs for combating coronavirus disease 19.IMPORTANCEIn addition to human angiotensin-converting enzyme 2, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can utilize alternative cofactors to facilitate viral entry. In this study, we discovered that histamine receptor H1 (HRH1) not only functions as an independent receptor for SARS-CoV-2 but also synergistically enhances ACE2-dependent viral entry by directly interacting with ACE2. Further studies have demonstrated that HRH1 facilitates the entry of SARS-CoV-2 by directly binding to the N-terminal domain of the spike protein. Conversely, antihistamine drugs, primarily HRH1 antagonists, can competitively bind to HRH1 and thereby prevent viral entry. These findings revealed that the administration of repurposable antihistamine drugs could be a therapeutic intervention to combat coronavirus disease 19.

Novel therapeutic receptor agonists and antagonists in allergic conjunctivitis.

PURPOSE OF REVIEW: Allergic conjunctivitis is characterized by the development of pathophysiological changes to the ocular surface, which occurs when pro-allergic and pro-inflammatory mediators interact with their cognate receptors expressed on immune and nonimmune cells. Traditional treatments with antihistamines and corticosteroids provide relief, but there is a need for more efficacious and tolerable long-term therapy with a better safety profile. This article aims to provide an overview of the mode of action and clinical application of agonist therapies targeting glucocorticoid, melanocortin, and toll-like receptors, as well as antagonist therapies targeting cytokine, chemokine, integrin, and histamine receptors. RECENT FINDINGS: There has been considerable advancement in immunology and pharmacology, as well as a greater understanding of the cellular and molecular mechanisms of allergic conjunctivitis. Recent research advancing therapy for allergic conjunctivitis has focused on developing synthetic molecules and biologics that can interfere with the process of the allergic immune reaction. SUMMARY: This review discusses novel therapeutic receptors being explored agonistically or antagonistically to develop alternative treatment options for allergic conjunctivitis. These novel approaches hold promise for improving the management of allergic eye diseases, offering patients hope for more effective and safer treatment options in the future.

Irritable bowel syndrome: When food is a pain in the gut.

Irritable bowel syndrome (IBS) is a chronic gastrointestinal condition associated with altered bowel habits and recurrent abdominal pain, often triggered by food intake. Current treatments focus on improving stool pattern, but effective treatments for pain in IBS are still lacking due to our limited understanding of pathophysiological mechanisms. Visceral hypersensitivity (VHS), or abnormal visceral pain perception, underlies abdominal pain development in IBS, and mast cell activation has been shown to play an important role in the development of VHS. Our work recently revealed that abdominal pain in response to food intake is induced by the sensitization of colonic pain-sensing neurons by histamine produced by activated mast cells following a local IgE response to food. In this review, we summarize the current knowledge on abdominal pain and VHS pathophysiology in IBS, we outline the work leading to the discovery of the role of histamine in abdominal pain, and we introduce antihistamines as a novel treatment option to manage chronic abdominal pain in patients with IBS.

What Are Food Allergies?

This JAMA Patient Page describes the causes, symptoms, risk factors, diagnosis, and treatment of food allergies.

In utero exposure to antihistamines and risk of hepatocellular carcinoma in a multigenerational cohort.

BACKGROUND: Growing evidence suggests that liver disease originates in early life. Antihistamines cross the placenta and are frequently prescribed to pregnant women to treat nausea and vomiting, as well as allergy and asthma symptoms. Exposure to antihistamines in utero may impact the developing liver by reprogramming or inducing epigenetic changes in fetal hepatocytes. METHODS: We examined in utero exposure to antihistamines and the risk of HCC in the Child Health and Development Studies, a multigenerational cohort that enrolled pregnant women in the East Bay, CA, between 1959 and 1966 (n=14,507 mothers and 18,751 liveborn offspring). We reviewed mothers' medical records to identify those prescribed antihistamines during pregnancy, and diagnoses of HCC in adult (age ≥18 y) offspring were identified by linkage with a population-based cancer registry. Cox proportional hazard models were used to estimate adjusted hazard ratios, with follow-up accrued from birth through cancer diagnosis, death, or last contact. RESULTS: About 15% of offspring (n=2759 of 18,751) were exposed in utero to antihistamines. Chlorpheniramine (51.8%) and diphenhydramine (15.4%) were the 2 most commonly prescribed antihistamines. Any in utero exposure was not associated with HCC (adjusted hazard ratio: 2.76, 95% CI: 0.70, 10.89), but the association differed by timing of exposure. Offspring exposed to antihistamines in the first or second trimester had a higher risk of HCC compared to offspring not exposed (adjusted hazard ratio: 4.64, 95% CI: 1.21, 17.78). Similarly, incidence rates were 4.3 per 100,000 (95% CI: 0.9, 12.6) for offspring exposed in the first or second trimester compared to 1.0 per 100,000 (95% CI: 0.3, 2.1) for offspring not exposed. CONCLUSIONS: In utero exposure to antihistamines in early pregnancy may increase the risk of HCC in adulthood.

Stimulation of central histaminergic transmission attenuates diazepam-induced motor disturbance on rota-rod and beam walking tests in mice.

Diazepam administration has been shown to influence the release of histamine in various brain areas involved in motor behavior. Therefore, the present study explored the plausible regulatory role of the central histaminergic system in diazepam-induced deficits in motor performance in mice using the rota-rod and beam walking tests. In this study, several doses of diazepam (0.5, 1, 2, and 3 mg/kg, i.p.) were assessed in mice for changes in motor performance on the rota-rod and beam walking test. In addition, the brain histamine levels were determined after diazepam administration, and the diazepam-induced motor deficits were assessed in mice, pretreated centrally (intracerebroventricular) with histaminergic agents such as histamine (0.1, 10 µg), histamine precursor (L-histidine: 0.1, 2.5 µg), histamine neuronal releaser/H 3 receptor antagonist (thioperamide: 0.5, 10 µg), H 1 and H 2 receptor agonist [2-(3-trifluoromethylphenyl) histamine (FMPH: 0.1, 6.5 µg; amthamine: 0.1, 5 µg)/antagonist (H 1 : cetirizine 0.1 µg) and (H 2 : ranitidine: 50 µg)]. Results indicate that mice treated with diazepam at doses 1, 2 mg/kg, i.p. significantly increased the brain histamine levels. Moreover, in mice pretreated with histaminergic transmission-enhancing agents, the diazepam (2 mg/kg, i.p.)-induced motor incoordination was significantly reversed. Contrastingly, diazepam (1 mg/kg, i.p.) in its subeffective dose produced significant motor deficits in mice preintracerebroventricular injected with histamine H 1 and H 2 receptor antagonists on both the employed tests. Therefore, it is postulated that endogenous histamine operates via H 1 and H 2 receptor activation to alleviate the motor-impairing effects of diazepam.

[Second-Generation Antihistamines for Preventing Hypersensitivity Reactions during Anticancer Therapy-A Retrospective Study].

Hypersensitivity reactions are an adverse effect of anticancer drug therapy. Prophylactic administration of antiallergic drugs and steroids is recommended when administering drugs associated with a high hypersensitivity reaction incidence. First-generation antihistamines are generally used in this setting. These medications, however, induce drowsiness and sedation due to their inhibitory effects on the central nervous system. They are contraindicated in patients with angle-closure glaucoma and prostatic hyperplasia. Second-generation antihistamines are used as alternative drugs for such cases in our hospital. This study investigated the use of second-generation antihistamines at our hospital and examined their efficacy and safety. A total of 7 second-generation antihistamines were used at our hospital. Approximately 90% of the target patients were shifted from first-generation antihistamines to bilastine or desloratadine. The most frequent reasons for changing to second- generation antihistamines were drowsiness(32.3%)and car driving(24.2%). No central inhibitory side effects were observed upon consumption of second-generation antihistamines. Only 2 patients(3.2%)developed hypersensitivity reactions after changing to second-generation antihistamines. Our findings suggest that second-generation antihistamines are effective in preventing hypersensitivity reactions. These medications may be used in patients who have concerns regarding the central inhibitory side effects of first-generation antihistamines or their potential to exacerbate comorbidities. Their use can help improve the safety of anticancer drug therapy.

The role of histamine and its receptors in breast cancer: from pathology to therapeutic targets.

Breast cancer is the most common malignancy in women, and despite the development of new treatment methods and the decreasing mortality rate in recent years, one of the clinical problems in breast cancer treatment is chronic inflammation in the tumor microenvironment. Histamine, an inflammatory mediator, is produced by tumor cells and can induce chronic inflammation and the growth of some tumors by recruiting inflammatory cells. It can also affect tumor physiopathology, antitumor treatment efficiency, and patient survival. Antihistamines, as histamine receptor antagonists, play a role in modulating the effects of these receptors in tumor cells and can affect some treatment methods for breast cancer therapy; in this review, we investigate the role of histamine, its receptors, and antihistamines in breast cancer pathology and treatment methods.

Treatment with Antihistamines and the Risk of Liver Cancer in Patients with Viral Hepatitis: A Multi-Center Cohort Study.

Background: The effects of antihistamines on cancer risk and prognosis have been inconsistent across cancers. The aim of this multi-center cohort study was to investigate the association between antihistamine use and the risk of liver cancer in individuals with viral hepatitis. Methods: This multi-center cohort study included individuals diagnosed with hepatitis B or hepatitis C between January 2008 and March 2022. For antihistamine-treated patients, the index date was the date of antihistamine prescription, and for non-users, it was the date of hepatitis diagnosis. Participants were followed for five years, with the primary outcome of interest being new-onset liver cancer. The incidence rate and the adjusted hazard ratio (aHR) along with its 95% confidence interval (CI) of the outcome were calculated. Subgroup analyses were conducted, stratified by types of viral hepatitis including hepatitis C and hepatitis B. An additional validation study was performed. Results: The study included a total of 7748 patients with viral hepatitis. The incidence rate was 12.58 per 1000 person-years in patients with viral hepatitis on antihistamines, compared to 3.88 per 1000 person-years in those without antihistamine use. After adjusting for factors including age, sex, body mass index (BMI), comorbidities, laboratory data of liver function tests, comedications, and the use of antiviral therapies, the risk of new-onset liver cancer was significantly higher in patients on antihistamines (aHR = 1.83, 95% CI, 1.28-2.60). In patients with hepatitis C, the incidence rate in the antihistamine group was 15.73 per 1000 person-years, while non-users had a rate of 4.79 per 1000 person-years. Patients with hepatitis C on antihistamines had a significantly higher risk of developing liver cancer (aHR = 3.24, 95% CI, 2.16-4.86). Conclusions: This multi-center cohort study reported an increased risk of liver cancer in patients with hepatitis B or hepatitis C treated with antihistamines. Long-term follow-up studies are warranted to validate the findings.