The Efficacy of Bepotastine Besilate Compared With Hydroxyzine Pamoate for Preventing Infusion Reactions to the First Dose of Rituximab in Patients With Non-Hodgkin Lymphoma: Protocol for a Phase II, Double-Blind, Multicenter Randomized Trial.

BACKGROUND: Rituximab, an anti-CD20 monoclonal antibody, can cause infusion reactions (IRs), especially during the initial rituximab infusion therapy. Generally, patients are administered a histamine H1-receptor antagonist before the rituximab infusion, along with an antipyretic analgesic, to prevent or reduce IRs. Multiple retrospective case-control studies indicate that the second generation of histamine H1-receptor antagonists might be more effective than the first generation in suppressing IRs caused by the rituximab infusion. OBJECTIVE: This study aimed to assess the efficacy of first- and second-generation histamine H1-receptor antagonists for preventing IRs resulting from the initial infusion of rituximab in patients diagnosed with non-Hodgkin lymphoma. METHODS: This is a phase II, double-blind, active-controlled randomized trial. It will be a multicenter study conducted across 3 facilities that aims to enroll a total of 40 patients diagnosed with non-Hodgkin lymphoma who will receive their initial rituximab infusion. Participating patients will be administered hydroxyzine pamoate or bepotastine besilate, representing first- or second-generation histamine H1-receptor antagonists, respectively. This will be combined with 400-mg acetaminophen tablets taken approximately 30 minutes before the first infusion of rituximab. The primary end point of this trial is to assess severe IRs, equivalent to grade 2 or higher as defined by the National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0, that occur within a 4-hour period after the initiation of rituximab infusion. The secondary end points include assessing the severity of the initial IR, the maximum severity of the IR, and the duration between rituximab infusion initiation and the onset of the first IR within a 4-hour period. Additionally, the trial will evaluate histamine H1-receptor antagonist-induced drowsiness using the visual analogue scale, with each patient providing their individual response. RESULTS: This study began with patient recruitment in April 2023, with 17 participants enrolled as of November 12, 2023. The anticipated study completion is set for February 2026. CONCLUSIONS: This study is the first randomized controlled trial comparing the effects of oral first- and second-generation histamine H1-receptor antagonists in preventing IRs induced by the initial administration of rituximab. The findings from this study hold the potential to establish the rationale for a phase III study aimed at determining the standard premedication protocol for rituximab infusion. TRIAL REGISTRATION: Japan Registry of Clinical Trials jRCTs051220169; https://jrct.niph.go.jp/latest-detail/jRCTs051220169. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/54882.

Epinastine Cream: A Novel Once-Daily Therapeutic Agent for Allergic Conjunctivitis.

Purpose: To investigate the in vivo efficacy of epinastine cream in type I allergic models. Methods: The dose, timing, and antiallergic effect of epinastine cream on the conjunctiva were evaluated postapplication to the eyelid skin of guinea pigs with histamine- or ovalbumin-induced allergic conjunctivitis. Additionally, we assessed its antiallergic effects on the skin postapplication to the dorsal skin of guinea pigs with ovalbumin-induced passive cutaneous anaphylaxis. Efficacy was estimated by determining the amount of dye that leaked from conjunctival or dorsal skin tissue vessels as a measure of vascular permeability, scoring the severity of allergic symptoms, and observing the scratching behaviors using clinical parameters. Results: In the histamine-induced conjunctivitis model, epinastine cream strongly inhibited conjunctival vascular permeability in a dose-dependent manner. The inhibitory effect of 0.5% epinastine cream 24 h postapplication was significantly higher than that of 0.1% epinastine hydrochloride ophthalmic solution 8 h postadministration. Additionally, the 0.5% epinastine cream inhibited conjunctival vascular permeability 15 min postapplication, and the effect was sustained over 24 h. Furthermore, the 0.5% epinastine cream effectively suppressed clinical symptom scores and exhibited ameliorated scratching bouts in conjunctival allergic reactions in the experimental allergic conjunctivitis model. Additionally, it significantly inhibited vascular permeability in skin allergic reactions in the passive cutaneous anaphylaxis model. Conclusions: The results suggest that epinastine cream is a strong, long-lasting, and skin-penetrating inhibitor of type I allergic reactions. The 0.5% epinastine cream applied once daily could be a promising, potent, and long-acting therapeutic agent for allergic conjunctivitis.

A case of atopic cough with aphonia showed a prominent response to a histamine H1 receptor antagonist.

A 33-year-old woman admitted to our hospital for further examination of severe non-productive cough lasting for about two months. Her symptom did not ameliorate by treatments including long acting ß2 agonists. She had a medical history of drug allergy to non-steroidal anti-inflammatory drugs. At the initial visit, she could not speak at all and communicated with us in writing. Chest auscultation revealed no wheezes, rhonchi and other crackles. Laboratory findings showed a mild eosinophilia with normal total and specific serum immunoglobulin E. The results of an electrocardiogram, a chest X-ray and a chest CT were unremarkable. A fractional exhaled nitric oxide value was within normal limit. Based on these observations, a diagnosis of atopic cough (AC) was suspected, and we started treatment with a histamine H1 receptor antagonist (H1-RA). She had become able to speak again in association with complete disappearance of cough by eight-weeks after treatment initiation, and her symptoms did not recur even after cessation of treatment. By the confirmation of remarkable clinical improvement in response to a H1-RA, a diagnosis of AC was made. To the best of our knowledge, this is the first report of an AC patient who presented severe cough with aphonia. J. Med. Invest. 70 : 281-284, February, 2023.

H1-Receptor Antagonist Olopatadine Inhibits MUC5AC Secretion by Conjunctival Goblet Cells.

The study examined the effect of H1-receptor antagonist olopatadine on the secretory function of cultured rat conjunctival goblet cells (CGC) assessed by enzyme-linked lectin assay employing UEA-I lectin. The level of mRNA for membrane-bound protein MUC16 in histaminestimulated CGC was assayed by reverse transcription PCR in the control and after preliminary application of olopatadine. The intracellular calcium concentration [Ca2+]i was measured by the calcium colorimetric method using GENMED kits. The effects of histamine and olopatadine on p-ERK level were assessed by Western blotting. Histamine up-regulated secretion of mucin MUC5AC and expression of membrane-bound protein MUC16 in CGC. In addition, it increased both [Ca2+]i and the level of phosphorylated ERK. These effects were diminished by preliminary application of olopatadine that probably acted via the ERK signaling pathway. Thus, olopatadine reduced [Ca2+]i and down-regulated ERK phosphorylation by binding to H1-receptors, thereby inhibiting secretion of mucin from histamine-stimulated CGC.

Repositioning of histamine H1 receptor antagonist: Doxepin inhibits viropexis of SARS-CoV-2 Spike pseudovirus by blocking ACE2.

The spread of the corona virus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been intensifying in the past year, posing a huge threat to global health. There is an urgent need for effective drugs and vaccines to fight the COVID-19, but their advent may not be quite fast. Drug repurposing is a feasible strategy in the current situation, which could greatly shorten drug development time and help to response quickly to the novel virus outbreak. It has been reported that histamine H1 receptor antagonists have broad-spectrum antiviral effects. Therefore, in this study, we aim to screen potential drugs among histamine H1 receptor antagonists that may inhibit SARS-CoV-2 infection. Based on the model of angiotensin-converting enzyme 2 (ACE2) overexpressing HEK293T cell membrane chromatography (CMC), five FDA-approved histamine H1 receptor antagonists were found to have bioaffinity to ACE2. Then we determined the interaction between these drugs and ACE2 by frontal analysis and surface plasmon resonance (SPR), which consistently demonstrated that these hits bind to ACE2 at micromolar levels of affinity. Through the pseudovirus assay, we finally identified that doxepin could inhibit SARS-CoV-2 spike pseudovirus from entering the ACE2-expressing cell, reducing the infection rate to 25.82%. These preliminary results indicate that the histamine H1 receptor antagonist, doxepin, is a viable drug candidate for clinical trials. Therefore, we hope the work timely provides rational help for developing anti-SARS-CoV-2 drugs to control the rapid spread of SARS-CoV-2.

[USEFULNESS OF RUPATADINE FOR PRURITUS OF PATIENTS WITH ATOPIC DERMATITIS].

BACKGROUND: Histamine H1 receptor antagonists (antihistamines) are recommended as adjunctive therapy for atopic dermatitis (AD). However, their long-term usefulness and the effect of updosing have not been clarified. PURPOSE: To analyzed the long-term usefulness and the effect of updosing of rupatadine, a second generation antihistamine, for patients with AD. METHODS: Efficacy and safety of rupatadine were evaluated in 66 AD patients, including 50 patients with dose escalation by post hoc analysis of the phase III trial of rupatadine for Japanese patients with pruritus associated with skin diseases. RESULTS: The mean score at baseline total pruritus score (TPS) was 4.682. It decreased to 3.885 at 2 weeks, and 2.376 at 52 weeks by rupatadine administration. The change (of one week after baseline TPS) was significant. Baseline TPS of dose escalation groups, either after 2 weeks or after week 4, were higher than those of 10mg maintenance dose cases, but no significant difference was shown in the change from baseline TPS among the groups at 52 weeks. The occurrence of adverse drug reactions and somnolence were observed in 19.7% and 15.2% of the subjects. CONCLUSION: These results suggest the long-term usefulness of rupatadine for pruritus in AD.

Phenothiazine antipsychotics exhibit dual properties in pseudo-allergic reactions: Activating MRGPRX2 and inhibiting the H1 receptor.

Phenothiazines are a class of antipsychotics that share the same tricyclic structure and are widely used in clinical settings. Adverse reactions from these drugs, however, have been regularly reported, with allergic skin reactions noted in some cases. Nevertheless, the mechanisms underlying anaphylaxis by these drugs have not been described. In the present study, we found that phenothiazine antipsychotics increased calcium mobilization and activated mast cells to release ß-hexosaminidase, histamine, and tumor necrosis factor-α via Mas-related G-protein-coupled receptor member X2 (MRGPRX2) in vitro. In addition, they induced histamine release in serum via Mrgprb2 in C57BL/6 mice without Evans blue extravasation or paw swell. Further experiments indicated these drugs had good interaction with the histamine H1 receptor (H1R) and show an anti-calcium mobilization effect on H1R-HEK293 cells, which confirmed a potential antagonist effect of these drugs on the H1R. The molecular docking and activity experiments indicated that the N-methyl substitution on the side chain of these drugs played a significant role in activating MRGPRX2, while the phenothiazine tricyclic ring was associated with the inhibiting effect on the H1R. Therefore, due to their dual properties of increasing histamine levels without obvious allergic symptoms, clinicians should be highly vigilant for damage from histamine accumulation and long-term inflammatory reactions during the clinical use of phenothiazine antipsychotics.

Practical and Sustainable Synthesis of Optically Pure Levocabastine, a H1 Receptor Antagonist.

A practical and sustainable method for the synthesis of levocabastine hydrochloride (1), a H1 receptor antagonist for the treatment of allergic conjunctivitis, that can be applied to the industrial production of the compound has been developed. Substantial improvements over the previously reported procedure are achieved via efficient preparation of an optically active key intermediate (5) without chiral resolution and with a more effective detosylation, which complements the previous procedure. Notably, our process requires no chromatographic purification and provides levocabastine hydrochloride in greater than 99.5% purity in a 14.2% overall yield.

Identification of selective 8-(piperidin-4-yloxy)quinoline sulfone and sulfonamide histamine H1 receptor antagonists for use in allergic rhinitis.

A series of potent, selective and long-acting quinoline-based sulfonamide human H1 histamine receptor antagonists, designed for once-daily intranasal administration for the treatment of rhinitis were developed. Sulfonamide 33b had a slightly lower affinity for the H1 receptor than azelastine, had low oral bioavailability in the rat and dog, and was turned over to five major metabolites. Furthermore, 33b had longer duration of action than azelastine in guinea pigs, lower rat brain-penetration, and did not cause time dependent inhibition of CYP2D6 or CYP3A4. The clinical dose in humans is expected to be low (approximately 0.5mg per day) based on the clinical dose used for azelastine and a comparison of efficacy data from animal models for 33b and azelastine.

Design of Phthalazinone Amide Histamine H1 Receptor Antagonists for Use in Rhinitis.

The synthesis of potent amide-containing phthalazinone H1 histamine receptor antagonists is described. Three analogues 3e, 3g, and 9g were equipotent with azelastine and were longer-acting in vitro. Amide 3g had low oral bioavailability, low brain-penetration, high metabolic clearance, and long duration of action in vivo, and it was suitable for once-daily dosing intranasally, with a predicted dose for humans of approximately 0.5 mg per day.

Evaluating the efficacy of epinastine ophthalmic solution using a conjunctivitis allergen challenge model in patients with birch pollen allergic conjunctivitis.

BACKGROUND: The efficacy of epinastine 0.05% ophthalmic solution for pollen allergic conjunctivitis has already been shown in a conjunctival allergen challenge (CAC) test using cedar pollen as a challenge. The present study investigated the efficacy of this solution against birch pollen conjunctivitis in a CAC test. METHODS: Ten adult subjects (eight males and two females) with asymptomatic birch pollen conjunctivitis were enrolled in this study. The average age of the subjects was 41.1 years. This study was conducted during a period without birch pollen dispersion. In each subject, the epinastine 0.05% ophthalmic solution was instilled in one eye, and an artificial tear fluid was instilled in the fellow eye in a double-blind manner. Five minutes or 4 h after the drug instillation, both eyes were challenged with an optimal concentration of birch pollen, and ocular itching and conjunctival hyperemia were then graded. Tears were collected before the drug instillation and 20 min after the pollen challenge, and the histamine level was measured. RESULTS: The ocular itching scores and palpebral conjunctival hyperemia scores of the epinastine-treated eyes were significantly lower than those of the contralateral control eyes when the eyes were pretreated with the drug 4 h before the CAC. There was a significant correlation between the tear histamine level and mean ocular itching score of three time points (3, 5 and 10 min) following the CAC in the control eyes but not the epinastine-treated eyes. CONCLUSIONS: Epinastine is effective in suppressing ocular itching and conjunctival hyperemia in birch pollen conjunctivitis.

Rupatadine: global safety evaluation in allergic rhinitis and urticaria.

INTRODUCTION: Rupatadine is a second-generation H1-antihistamine with dual affinity for histamine H1 and PAF receptors. Rupatadine is indicated for the treatment of allergic rhinitis and urticaria. AREAS COVERED: A Medline search was conducted to identify preclinical and clinical studies of rupatadine. This was supplemented with additional articles obtained from online sources. The focus of this review is on the safety profile of rupatadine. EXPERT OPINION: The review of these data indicates that rupatadine is highly selective for histamine H1-receptors, exhibits additional PAF antagonism in in vitro and in vivo studies, does not cross the blood-brain barrier, and has similar adverse events comparable with other second-generation antihistamines. Rupatadine is a safe and well tolerated drug in patients over 2 years old, with no central nervous system or cardiovascular effects and it can be taken with or without foods.

QT interval prolongation and torsade de pointes: Synergistic effect of flecainide and H1 receptor antagonists.

A high percentage of patients having atrial fibrillation (AF) presents with paroxysmal AF. Flecainide, the prototypic class Ic anti-arrhythmic drug is the most effective drug to maintain sinus rhythm in this subgroup of patients, though the drug has potential pro-arrhythmic effects. Furthermore, the H1 receptor antagonists are the most commonly prescribed drugs for the symptomatic treatment of pruritus. Despite having low number of adverse effects, the H1 receptor antagonists have cardiotoxic effects. Flecainide and H1 receptor antagonists present arrhythmic complications including QT interval prolongation and torsade de pointes (TdP). The case presented here is a 65-year-old female who was diagnosed of atrial fibrillation and presented with rashes in lower extremities. The patient was treated using flecainide and H1 receptor antagonists (loratadine and hydroxyzine) that prolonged QT interval and induced TdP. The concomitant administration of flecainide and H1 receptor antagonists seems to have a synergistic effect in QT interval prolongation and subsequent TdP. The concurrent administration of H1 receptor antagonists to patients receiving class Ic anti-arrhythmic drugs should be avoided in order to reduce arrhythmic risk in this population.

Argentinean Society of Experimental Pharmacology: Brief history and main scientific contributions to the discipline.

Argentina Biomedical Science has been historically strong. The development of Human and Veterinary Pharmacology in our country as a pivotal discipline has been acknowledged worldwide because of the quality of its contributions. Argentinean Society of Experimental Pharmacology (SAFE) is a non- profit association whose research fields include Experimental and Clinical Pharmacology. SAFE main goals are described as follow (a) To meet active researchers for studying concerns regarding Experimental and Clinical Pharmacology (b) To launch an initiative for development of the discipline in mainly our country and other collaborative countries worldwide (c) To spread the pharmacological know-how obtained from different research teams (d) To strengthen relations between pharmacologists (e) To facilitate the presentation and discussion of scientific papers. This current article shows the SAFE's more important scientific contribution to pharmacology through its former research scientists to the present.

Asymmetric synthesis of H1 receptor antagonist (R,R)-clemastine.

The first asymmetric synthesis of (R,R)-clemastine (1) has been accomplished by the coupling of (R)-tertiary alcohol 2 and (R)-chloroethylpyrrolidine 3 via O-alkylation. (R)-Tertiary alcohol 2 was synthesized by stereoselective alkylation of chiral α-benzyloxy ketone with Grignard reagent via chelation-controlled 1,4-asymmetric induction. In the reaction, chiral benzyl group acts as a chiral auxiliary as well as a protecting group. (R)-Chloroethylpyrrolidine 3 was prepared by asymmetric transformation starting with L-homoserine lactone, in which racemization-minimized N-allylation and ring-closing metathesis were involved as key steps.

The ability of H1 or H2 receptor antagonists or their combination in counteracting the glucocorticoid-induced alveolar bone loss in rats.

BACKGROUND: The aim of the present study was to compare between three possible osteoporotic treatments in prevention of glucocorticoid-induced alveolar bone loss. METHODS: Fifty adult female Wistar rats with an average weight 150-200 g were randomized into five groups: group I (control) was intraperitoneally injected with saline. The other experimental groups (II & III, IV & V) were intraperitoneally injected with 200 µg/100 g body weight dexamethasone. The experimental groups III, IV and V received intraperitoneal injection of 10 mg/kg/day pheniramine maleate (H1 receptor antagonist), ranitidine hydrochloride (H2 receptor antagonist) and concomitant doses of both H1 & H2 receptor antagonists respectively. After 30 days, the rats have been sacrificed. The mandibles were examined histologically, histochemically and histomorphometrically. The bone mineral density was measured using dual-energy X-ray absorptiometry (DEXA). RESULTS: Histopathologically the glucocorticoid group showed wide medullary cavities with wide osteocytic lacunae. These marrow cavities were reduced in the prophylactic groups (III, IV) but increased in group V. Bone histomorphometric analysis revealed improvement in static bone parameters in groups III and IV and deterioration in group V in comparison to group II. The DEXA revealed significant reduction in the bone mineral density in all experimental groups compared to the control group. CONCLUSIONS: In a rat model, the administration of H1 or H2 receptor antagonists separately could minimize the alveolar bone loss caused by the administration of glucocorticoids while concomitant administration of both H1 and H2 receptor antagonists deteriorated the bone condition.

Influence of the hippocampus on amino acid utilizing and cholinergic neurons within the nucleus accumbens is promoted by histamine via H1 receptors.

BACKGROUND AND PURPOSE: The influence of the neurotransmitter histamine on spontaneous and stimulation-evoked release of glutamate, aspartate, GABA and ACh in the nucleus accumbens (NAc) was investigated in vivo. EXPERIMENTAL APPROACH: Using the push-pull superfusion technique, histaminergic compounds were applied to the NAc and neurotransmitter release was assessed. In some experiments, the fornix/fimbria of the hippocampus was electrically stimulated by a microelectrode and evoked potentials were monitored in the NAc. KEY RESULTS: Superfusion of the NAc with the H1 receptor antagonist triprolidine (50 µM) decreased spontaneous outflow of glutamate, aspartate and ACh, while release of GABA remained unaffected. Superfusion with histamine elevated release of ACh, without influencing that of the amino acids. Electrical stimulation of the fornix/fimbria enhanced the output of amino acids and ACh within the NAc. The evoked outflow of glutamate and ACh was diminished on superfusion with triprolidine, while release of aspartate and GABA was not affected. Superfusion of the NAc with histamine intensified the stimulation-evoked release of glutamate and Ach. Histamine also elevated the stimulation-induced release of aspartate, without influencing that of GABA. Presuperfusion with triprolidine abolished the reinforced effect of histamine on stimulation-evoked transmitter release within the NAc. CONCLUSION AND IMPLICATIONS: Neuronal histamine activates H1 receptors and increases spontaneous release of glutamate, aspartate and ACh within the NAc. Stimulation of the hippocampal fornix/fimbria tract also enhances release of glutamate and ACh within the NAc and this effect is intensified by H1 receptor stimulation within the NAc. The latter effects, which are mediated by hippocampal afferences, might play an important role in mnemonic performance and in emotional processes such as anxiety and stress disorders.