Fexofenadine reduces nasal congestion in perennial allergic rhinitis

Co-treatment with Fexofenadine and Budesonide Increases FoxP3 Gene Expression in Patients with Allergic Rhinitis

BACKGROUND

T helper type 2 (Th2), Th17, and regulatory T cells (Tregs) play essential roles in the pathogenesis and control of allergic rhinitis (AR). Fexofenadine and budesonide are first-line treatments for AR. This study aimed to investigate the effect of co-treatment with fexofenadine and budesonide on the expression of Th2, Th17, and Treg-specific transcription factors (GATA-binding protein 3 [GATA-3], RAR-related orphan receptor gamma [RORγt], and forkhead box P3 [FoxP3], respectively) in AR patients.

METHODS

In this study, 29 AR patients were co-treated with fexofenadine and budesonide for 1 month. Blood was collected from AR patients before and after 1 month of treatment. The gene expression levels of GATA-3, RORγt, and FoxP3 transcription factors in blood samples were measured. In addition, serum immunoglobulin E (IgE) levels and eosinophil percentages in blood samples were determined.

FINDINGS

The expression level of FoxP3 increased significantly after treatment compared with that before treatment (P < .001). In contrast, GATA-3 and RORγt expression levels did not show any noticeable changes. In addition, the percentage of peripheral blood eosinophils significantly decreased (P < .01). Serum IgE levels decreased compared with those before treatment, but the difference was not statistically significant. Furthermore, the clinical symptoms of the patients improved compared with those before treatment.

CONCLUSION

Our results showed that combined treatment with fexofenadine and budesonide increased the expression level of the FoxP3 gene, decreased the percentage of peripheral blood eosinophils, and improved the clinical symptoms of AR patients. This regimen appears to improve disease symptoms, at least in part by increasing the Treg population and decreasing the eosinophil population.

Updates in the diagnosis and practical management of allergic rhinitis

INTRODUCTION

Allergic rhinitis (AR) is a widespread disease that can be associated with other conditions, including conjunctivitis, rhinosinusitis, asthma, food allergy, and atopic dermatitis. Diagnosis is based on the history and documentation of sensitization, such as the production of allergen-specific IgE, preferably using molecular diagnostics. Treatments are based on patient education, non-pharmacological and pharmacological remedies, allergen-specific immunotherapy (AIT), and surgery. Symptomatic treatments mainly concern intranasal/oral antihistamines and/or nasal corticosteroids.

AREAS COVERED

This review discusses current and emerging management strategies for AR, covering pharmacological and non-pharmacological remedies, AIT, and biologics in selected cases with associated severe asthma. However, AIT presently remains the unique causal treatment for AR.

EXPERT OPINION

The management of allergic rhinitis could include new strategies. In this regard, particular interest should be considered in the fixed association between intranasal antihistamines and corticosteroids, probiotics and other natural substances, and new formulations (tablets) of AIT.

House dust mites-driven allergic rhinitis: could its natural history be modified?

INTRODUCTION

Allergic rhinitis (AR) is the most common IgE-mediated disease. House dust mites (HDMs)-sensitization is the main cause of AR. HDM-driven AR is characterized by a typical natural history consisting of possible progression to asthma. Allergen Immunotherapy (AIT) is, at present, a unique treatment to modify the natural history of allergic diseases. Tablets AIT (TAIT) represents a new era in AIT. There is evidence that TAIT could prevent asthma in AR patients.

AREAS COVERED

The literature search methodology was based on the articles cited by PubMed from 1980 to 2020. AIT's rationale is to restore an immunological and, consequently, clinical tolerance toward the causal allergen. The progression from rhinitis to asthma may be influenced by a relevant risk factor, such as the persistent type 2 inflammation of airways. HDMs are perennial allergens and allergen exposure is the condicio sine qua non to maintain inflammation. AIT could modify the progression toward asthma restoring physiologic immune response to the causal allergen and consequently dampening type 2 inflammation.

EXPERT OPINION

Patients with HDM-driven AR are susceptible to develop asthma over time. Many studies explored this topic. Cross-sectional and longitudinal studies identified some markers which predict the risk of developing asthma. They include bronchial airflow limitation, bronchial hyperresponsiveness, type 2 inflammation, and rhinitis duration. TAIT could block this progression by acting on this vicious circle. Future studies should explore this issue using adequate methodology.

Antihistamines in children and adolescents: A practical update

Histamine is a chemical mediator, released predominantly by tissue mast cells, circulating basophils, and neurons, which are activated in response to various immunological and non-immunological stimuli. Histamine has to bind to specific receptors to exert its physiological and pathophysiological functions. Endogenous histamine is the main mediator of the immediate allergic response, which moreover, performs other multiple functions, including regulation of gastric secretion, neurotransmission in the central nervous system, and immunomodulatory activity. The involvement of histamine in various disorders and the importance of receptors in the clinical features have relevant implications in clinical practice. Anti-H1 antihistamines contrast the histamine-dependent effects, mainly concerning nasal symptoms and cutaneous itching and wheal. Antihistamines are among the most prescribed drugs in pediatric care. This review updates the practical use of antihistamines in children and adolescents.

Consensus statement of the Italian society of pediatric allergy and immunology for the pragmatic management of children and adolescents with allergic or immunological diseases during the COVID-19 pandemic

The COVID-19 pandemic has surprised the entire population. The world has had to face an unprecedented pandemic. Only, Spanish flu had similar disastrous consequences. As a result, drastic measures (lockdown) have been adopted worldwide. Healthcare service has been overwhelmed by the extraordinary influx of patients, often requiring high intensity of care. Mortality has been associated with severe comorbidities, including chronic diseases. Patients with frailty were, therefore, the victim of the SARS-COV-2 infection. Allergy and asthma are the most prevalent chronic disorders in children and adolescents, so they need careful attention and, if necessary, an adaptation of their regular treatment plans. Fortunately, at present, young people are less suffering from COVID-19, both as incidence and severity. However, any age, including infancy, could be affected by the pandemic.Based on this background, the Italian Society of Pediatric Allergy and Immunology has felt it necessary to provide a Consensus Statement. This expert panel consensus document offers a rationale to help guide decision-making in the management of children and adolescents with allergic or immunologic diseases.

Lertal®, a multicomponent nutraceutical, could reduce the use of antihistamines in children with allergic rhinoconjunctivitis

Antihistamines are the cornerstone treatment of allergic rhinitis (AR). To quantify the antihistaminic consume is particularly relevant in clinical practice, since a remarkable use is usually associated with severe symptoms. The aim of the study was to measure the use of antihistamines in two groups of children suffering from AR. The first group took a course of a nutraceutical (Lertal®) before the observation (active group, AG); a second one was considered as control (control group, CG). Both groups took antihistamines on demand. The children were visited at baseline and after 1 year. The number of days of antihistaminic use was the primary outcome. Children in AG had a significant reduced number of antihistamines use in comparison with CG (p=0.008). In conclusion, the current study showed that a course with a multicomponent nutraceutical could reduce the use of symptomatic antihistamines in children with allergic rhinoconjunctivitis. (www.actabiomedica.it)

Inflammation, infection, and allergy of upper airways: new insights from national and real-world studies

The upper airways (UA) should be considered as a functional unit. Current functional anatomy divides URT in three, mutually dependent, "junction boxes": i) the ostio-meatal complex (OMC), ii) the spheno-ethmoidal recess (SER), and iii) the rhinopharynx (RP). Correct ventilation and effective mucociliary clearance of these sites significantly affect the healthy physiology of the entire respiratory system. The OMC, SER, and RP obstruction is the first pathogenic step in the inflammatory/infectious cascade of UA disorders. The inflammation of the respiratory mucosa is the main pathogenic factor for airway obstruction. Moreover, bacterial biofilm (a strategy modality of bacterial survival) is an important local cause of systemic antibiotic ineffectiveness, recurrent infections, and antibiotic resistance. Health microbiota guarantees UA wellness; on the contrary, dysbiosis promotes and worsens UA infections. Allergy, namely type 2 inflammation, is a common cause of UA obstruction such as promoting in turn infections. Fiberoptic endoscopy is a mandatory diagnostic tool in clinical practice. Nasal cytology, mainly concerning flow cytometry, allows defining rhinitis phenotypes so allowing a precision medicine approach. Several conventional therapeutic approaches are available, but efficacy and safety should be ever properly considered before the prescription. Also, complementary medicine plays a fruitful role in the management of UA diseases. National and real-world studies are reported and discussed as they may be useful in daily clinical practice.

VAS for assessing the perception of antihistamines use in allergic rhinitis

The quantification of the antihistamines’ consumption is particularly relevant in clinical practice, since their remarkable use is usually associated with severe symptoms. The aim of the study was to measure the visual analogue scale (VAS) for assessing the patient’s perception about antihistamines use in patients with allergic rhinitis. 103 patients (49 males, mean age 35.9 years) with allergic rhinitis due to Parietaria pollen were evaluated retrospectively. They recorded monthly the number of antihistamine tables they took during the pollen season (lasting for about 5 months). There was a strong relationship (r= 0.921 Pearson; p<0.0001) between the number of tablets and the VAS score. The assessment of the perception of the antihistamines use by VAS could be an easy and quick tool in the management of patients with allergic rhinitis in clinical practice. (www.actabiomedica.it)

BSACI guideline for the diagnosis and management of allergic and non-allergic rhinitis (Revised Edition 2017; First edition 2007)

This is an updated guideline for the diagnosis and management of allergic and non-allergic rhinitis, first published in 2007. It was produced by the Standards of Care Committee of the British Society of Allergy and Clinical Immunology, using accredited methods. Allergic rhinitis is common and affects 10-15% of children and 26% of adults in the UK, it affects quality of life, school and work attendance, and is a risk factor for development of asthma. Allergic rhinitis is diagnosed by history and examination, supported by specific allergy tests. Topical nasal corticosteroids are the treatment of choice for moderate to severe disease. Combination therapy with intranasal corticosteroid plus intranasal antihistamine is more effective than either alone and provides second line treatment for those with rhinitis poorly controlled on monotherapy. Immunotherapy is highly effective when the specific allergen is the responsible driver for the symptoms. Treatment of rhinitis is associated with benefits for asthma. Non-allergic rhinitis also is a risk factor for the development of asthma and may be eosinophilic and steroid-responsive or neurogenic and non- inflammatory. Non-allergic rhinitis may be a presenting complaint for systemic disorders such as granulomatous or eosinophilic polyangiitis, and sarcoidoisis. Infective rhinitis can be caused by viruses, and less commonly by bacteria, fungi and protozoa.

Optimal Duration of Allergic Rhinitis Clinical Trials

OBJECTIVE: Guidelines have been published by the Food and Drug Administration (FDA) and the European Agency for the Evaluation of Medicinal Products (EMEA) for the conduct of seasonal allergic rhinitis (SAR) and perennial allergic rhinitis (PAR) studies. These guidelines have differences regarding the duration of such trials: the FDA suggests 2 weeks for SAR and 4 weeks for PAR but the EMEA suggests 2 to 4 weeks for SAR and 6 to 12 weeks for PAR trials. In the interest of global harmonization, it would be desirable to have a uniform duration of such trials so that investigators, internationally, would be able to readily compare results for various types of treatments based on a single standard. Therefore, we performed an evidence-based review to answer the clinical question, What is the optimal duration for SAR and PAR clinical trials?

METHODS: We performed a MEDLINE search of the published literature from 1995 to the present. We used appropriate search terms, such as allergic rhinitis, seasonal allergic rhinitis, perennial allergic rhinitis, SAR, and PAR, to identify pertinent articles. These articles were reviewed and graded according to the evidence quality.

RESULTS: After an initial screening of more than 300 articles, 138 articles were analyzed thoroughly. No study specifically addressed the question of the optimal duration of SAR or PAR clinical trials.

CONCLUSIONS: We conclude that the current FDA (draft) guidelines calling for a study length of 2 weeks for the assessment of drug efficacy for SAR and 4 weeks for the study of drug efficacy in PAR are appropriate and that longer study periods are not likely to add meaningfully to the assessment of drug efficacy.

Antihistamine therapy in allergic rhinitis

Antihistamines have long been a mainstay in the therapy for allergic rhinitis. Many different oral antihistamines are available for use, and they are classified as first generation or second generation based on their pharmacologic properties and side-effect profiles. The recent introduction of intranasal antihistamines has further expanded the role of antihistamines in the treatment of allergic rhinitis. Certain patient populations, such as children and pregnant or lactating women, require special consideration regarding antihistamine choice and dosing as part of rhinitis therapy.

Treatment of congestion in upper respiratory diseases

Congestion, as a symptom of upper respiratory tract diseases including seasonal and perennial allergic rhinitis, acute and chronic rhinosinusitis, and nasal polyposis, is principally caused by mucosal inflammation. Though effective pharmacotherapy options exist, no agent is universally efficacious; therapeutic decisions must account for individual patient preferences. Oral H₁-antihistamines, though effective for the common symptoms of allergic rhinitis, have modest decongestant action, as do leukotriene receptor antagonists. Intranasal antihistamines appear to improve congestion better than oral forms. Topical decongestants reduce congestion associated with allergic rhinitis, but local adverse effects make them unsuitable for long-term use. Oral decongestants show some efficacy against congestion in allergic rhinitis and the common cold, and can be combined with oral antihistamines. Intranasal corticosteroids have broad anti-inflammatory activities, are the most potent long-term pharmacologic treatment of congestion associated with allergic rhinitis, and show some congestion relief in rhinosinusitis and nasal polyposis. Immunotherapy and surgery may be used in some cases refractory to pharmacotherapy. Steps in congestion management include (1) diagnosis of the cause(s), (2) patient education and monitoring, (3) avoidance of environmental triggers where possible, (4) pharmacotherapy, and (5) immunotherapy (for patients with allergic rhinitis) or surgery for patients whose condition is otherwise uncontrolled.

A review of the efficacy of desloratadine, fexofenadine, and levocetirizine in the treatment of nasal congestion in patients with allergic rhinitis

BACKGROUND

Nasal congestion is the most troublesome symptom of allergic rhinitis (AR). First-generation and older second-generation antihistamines, while effective against nasal itching, sneezing, and rhinorrhea, have limited efficacy in relieving nasal congestion.

OBJECTIVE

This review included nasal challenge studies and clinical trials that reported the effects on nasal congestion of the newer second-generation antihistamines desloratadine, fexofenadine, and levocetirizine.

METHODS

MEDLINE and EMBASE were searched for nasal challenge studies and clinical trials published in English between January 1, 1991, and January 31, 2009, using the following terms, alone or in combination: antihistamines, second-generation antihistamines, allergic rhinitis, intermittent allergic rhinitis, perennial allergic rhinitis, persistent allergic rhinitis, seasonal allergic rhinitis, nasal challenge, nasal blockage, and nasal congestion. Studies that were not active or placebo controlled, that did not evaluate change in nasal congestion scores, or that focused on treatments other than desloratadine, fexofenadine, and levocetirizine for nasal congestion associated with AR were excluded.

RESULTS

Twenty-six clinical trials met the criteria for inclusion in the review. In 11 placebo-controlled trials that included objective assessment of nasal congestion, desloratadine, fexofenadine, and levocetirizine were associated with reductions in the severity of nasal congestion through maintenance of nasal airflow. The mean AUC for nasal airflow over 6 hours was significantly greater with desloratadine compared with placebo in 3 studies (P < 0.05); placebo-controlled trials of fexofenadine and levocetirizine had similar results. In 25 placebo- and active-controlled trials that reported subject-rated symptom scores, the 3 newer antihistamines were efficacious in the treatment of nasal congestion associated with AR. In 10 trials that reported objective and/or subjective measures, desloratadine was associated with significant improvements in nasal congestion compared with placebo (P < or = 0.05), beginning as early as the first 2 hours after allergen challenge. Fexofenadine was associated with significantly lower nasal congestion scores compared with placebo in 4 studies (P <- 0.05); nasal congestion scores were significantly reduced with levocetirizine in 3 placebo-controlled trials (P < or = 0.005).

CONCLUSIONS

In the studies reviewed, desloratadine, fexofenadine, and levocetirizine were effective in relieving the nasal congestion associated with AR compared with placebo. This effect began as early as day 2 and was consistent and progressive throughout treatment. Desloratadine, fexofenadine, and levocetirizine are appropriate options for the treatment of nasal congestion in patients with AR.

Complexities of diagnosis and treatment of allergic respiratory disease in the elderly

Atopic diseases such as rhinitis and asthma are relatively common in children and young adults. However, many patients aged >65 years are also affected by these disorders. Indeed, the literature suggests that between 3-12% and 4-13% of individuals in this age range have allergic rhinitis and asthma, respectively. However, these numbers are most likely underestimates because atopic diseases are frequently not considered in older patients. The diagnosis of both allergic rhinitis and asthma in older patients is more difficult than in younger patients because of a wide differential diagnosis of other diseases that can produce similar symptoms and must be excluded. Furthermore, treatment of these disorders is complicated by the potential for drug interactions, concern about the adverse effects of medications, in particular corticosteroids, and the lack of drug trials specifically targeting treatment of older patients with allergic rhinitis and asthma.

Levocetirizine modulates lymphocyte activation in patients with allergic rhinitis

Levocetirizine, a second generation non-sedating antihistamine that blocks the H(1) histamine receptor, may exhibit immunoregulatory properties that augment its primary pharmacological mechanism. To investigate this possibility, 13 Kuwaiti seasonal allergic rhinitis (SAR) patients were treated with levocetirizine for four weeks in comparison with a 7-member placebo-treated control group, followed by clinical evaluation and flow cytometric analysis of peripheral venous blood for inflammatory cell and lymphocyte subpopulation profiles. Relative to the controls, levocetirizine-treated patients exhibited an expected reduction in early phase allergic symptoms, including sneezing (P<0.001), nasal itching (P<0.01), nasal congestion, and running nose (P<0.001); reduced percentages of eosinophils (P<0.05); and three subpopulations of activated T lymphocytes: CD4+CD29+, CD4+CD212+, and CD4+CD54+ (P<0.05). Levocetirizine treatment also correlated with a significant increase in the percentage of CD4+CD25+ T cells (P<0.001). The ability of levocetirizine to reduce percentage representation of cell phenotypes known to contribute to inflammatory tissue damage (eosinophils, CD4+CD29+, CD4+CD212+, and CD4+CD54+) and expand percentages of CD4+CD25+, which may include protective immunoregulatory (Treg) cells, indicates that the drug has pharmacological potential beyond the immediate effects of H(1) histamine-receptor inhibition. Although the present data does not define a therapeutic mechanism, the results reported here establish important trends that may be used to guide future mechanistic examination of immunoregulatory capacity of H(1) inhibitors.

Clinical benefits of combination treatment with mometasone furoate nasal spray and loratadine vs monotherapy with mometasone furoate in the treatment of seasonal allergic rhinitis

BACKGROUND

Intranasal corticosteroids and nonsedating antihistamines are the drug classes most often prescribed to treat allergic rhinitis (AR). Treatment guidelines recommend a combination of these agents for moderate-to-severe AR. However, clinical studies have found that combining an antihistamine with an intranasal corticosteroid provides few or no advantages over monotherapy with an intranasal corticosteroid.

OBJECTIVE

To compare the efficacy of mometasone furoate nasal spray (NS) plus loratadine with that of monotherapy with the individual agents in patients 12 years and older with at least a 2-year history of seasonal AR.

METHODS

In a multicenter, randomized, double-blind, parallel-group, placebo-controlled clinical study, 702 patients were randomized to receive mometasone furoate NS, 200 microg, plus loratadine, 10 mg (n = 169); mometasone furoate NS, 200 microg (n = 176); loratadine, 10 mg (n = 181); or placebo (n = 176) once daily for 15 days. Primary efficacy variables were total nasal symptom score (TNSS) and total symptom score (TSS) as recorded on diary cards.

RESULTS

No statistically significant differences were observed between mometasone furoate NS plus loratadine and mometasone furoate NS monotherapy for the primary efficacy variables. For TNSS and TSS, all 3 active drug therapies were more effective than placebo (P < or = .02). Both mometasone furoate NS treatment regimens were more effective than loratadine or placebo for TNSS (P < .01 for both) and TSS (P < or = .03 for both), whereas loratadine was more effective than placebo for TNSS only (P = .02).

CONCLUSIONS

Combination therapy with mometasone furoate NS and loratadine provided benefits similar to monotherapy with mometasone furoate NS for the symptoms of seasonal AR. Therefore, mometasone furoate NS monotherapy was shown to be an effective treatment for seasonal AR.

BSACI guidelines for the management of allergic and non-allergic rhinitis

This guidance for the management of patients with allergic and non‐allergic rhinitis has been prepared by the Standards of Care Committee (SOCC) of the British Society for Allergy and Clinical Immunology (BSACI). The guideline is based on evidence as well as on expert opinion and is for use by both adult physicians and paediatricians practicing in allergy. The recommendations are evidence graded. During the development of these guidelines, all BSACI members were included in the consultation process using a web‐based system. Their comments and suggestions were carefully considered by the SOCC. Where evidence was lacking, consensus was reached by the experts on the committee. Included in this guideline are clinical classification of rhinitis, aetiology, diagnosis, investigations and management including subcutaneous and sublingual immunotherapy. There are also special sections for children, co‐morbid associations and pregnancy. Finally, we have made recommendations for potential areas of future research.

The safety and efficacy of desloratadine for the management of allergic disease

Allergic disease is an increasing problem worldwide. Allergic rhinitis, an inflammatory response to an allergen, affects an estimated 20-40 million people in the US, while chronic idiopathic urticaria is a dermatoallergic condition that affects 0.1-3% of people in the US and Europe. The primary goals of treatment for allergic rhinitis are to reduce symptoms, which include sneezing, rhinorrhoea and nasal congestion, improve quality of life and prevent the sequelae associated with this disease, while the goal for chronic idiopathic urticaria is the rapid and prolonged control of symptoms. Quantitatively, histamine is the most abundant mediator present during an allergic episode - thus, antihistamines (historically called histamine H(1) receptor antagonists, now called H(1) receptor inverse agonists) are a first-line defense against allergic rhinitis and chronic idiopathic urticaria. Although first-generation antihistamines can cause sedation and cognitive impairment, second-generation antihistamines are relatively non-sedating and free of such adverse events owing to their comparative inability to penetrate the blood-brain barrier. Desloratadine is one such second-generation antihistamine and is indicated for the treatment of allergic diseases, including allergic rhinitis and chronic idiopathic urticaria. It has proven efficacy against the symptoms associated with seasonal and perennial allergic rhinitis, including nasal congestion, and chronic idiopathic urticaria. As a result, it has been shown to improve patients' quality of life. The safety and efficacy profiles of desloratadine are well established, and published postmarketing analyses have assessed >54 000 patients. Although earlier second-generation antihistamines have been associated with cardiovascular adverse effects, desloratadine has been shown to be safe and well tolerated at nine times the recommended dose. In addition, it has been shown to not interact with concomitantly administered drugs and food. Overall, current data indicate that desloratadine is a safe and effective treatment for allergic diseases.

Combining desloratadine and pseudoephedrine in the treatment of seasonal allergic rhinitis

Nonsedating antihistamines are a first-line therapy in the management of allergic rhinitis. They relieve the majority of the histamine-mediated symptoms of the condition, including rhinorrhea, sneezing, and pruritus. The nonsedating antihistamine desloratadine is effective in alleviating the symptoms of both seasonal and perennial allergic rhinitis. It may also have some decongestant properties, and thus help to alleviate nasal congestion. Administering desloratadine in combination with the decongestant pseudoephedrine may offer allergic rhinitis patients with moderate-to-severe nasal congestion the benefits of desloratadine's effectiveness for alleviating histamine-mediated symptoms plus pseudoephedrine's relief from nasal congestion. This drug profile reviews a combination therapy containing desloratadine and pseudoephedrine, approved in the USA for the relief of the symptoms of seasonal allergic rhinitis, including nasal congestion.

Emerging anti-inflammatory agents for allergic rhinitis

Allergic rhinitis (AR) is a high-prevalence disease, affecting 10-15% of the general population. AR is sustained by an IgE-mediated reaction, and by a complex inflammatory network of cells, mediators and cytokines that becomes chronic when exposure to allergen persists. A T helper 2 (TH2)-biased immune response is the basis for the allergic inflammation. The current therapeutic strategy is mainly based on drugs (antihistamines, nasal corticosteroids, cromones, decongestants) and allergen immunotherapy. Drugs are overall effective in controlling symptoms, but do not modify the immune background that leads to allergic inflammation, and safety concerns may be present especially for prolonged treatments. Immunotherapy can modify the allergic response, but there is still space for improvement. Nowadays, several approaches are under investigation to optimise the management of AR. On one hand, new drugs and antimediators are being developed; on the other hand, attempts are made to selectively block relevant signal pathways of allergic reaction. Finally, one of the major goals is to modify the TH2-biased immune response by improving the characteristics and modes of action of allergen immunotherapy.

Efficacy of fexofenadine in the prophylactic control of cat allergen-induced allergic rhinitis

BACKGROUND

To date, it is unknown whether fexofenadine mitigates the worsening of symptoms induced by the cat allergen Felis domesticus allergen 1.

OBJECTIVE

To determine the effects of a single dose of fexofenadine hydrochloride, 180 mg, in preventing and controlling cat allergen-induced allergic rhinitis symptoms using the cat room challenge model.

METHODS

This single-center, randomized, double-blind, placebo-controlled, 2-way crossover study consisted of a screening visit, 1 or 2 qualifying visits, and 2 treatment periods separated by a mean +/- SD washout period of 14 +/- 3 days. Patients were randomized to treatment sequence 1 (placebo followed by fexofenadine) or sequence 2 (fexofenadine followed by placebo). Baseline end points were obtained before study drug administration, and allergen challenges were initiated 1 1/2 hours after dosing. The primary end point was the change from predose baseline in the total symptom score (sum of rhinorrhea, itchy nose/palate/ throat, sneezing, and itchy/watery/red eyes) after 30 minutes of allergen exposure compared with placebo.

RESULTS

Of 211 patients screened, 66 were randomized and 63 completed the study. Mean change in the total symptom score from predose baseline was significantly less with fexofenadine compared with placebo 30 minutes after initiation of the cat allergen challenge (2 hours after dosing) (P = .03). The overall incidence of treatment-emergent adverse events was low and comparable for both groups.

CONCLUSION

Prophylactic treatment with a single dose of fexofenadine hydrochloride, 180 mg, significantly mitigated the worsening of allergic rhinitis symptoms induced by exposure to cat allergen compared with placebo use.

Allergic rhinitis: treatment based on patient profiles

Allergic rhinitis is a common medical condition characterized by nasal, throat, and ocular itching; rhinorrhea; sneezing; nasal congestion; and, less frequently, cough. The treatment of allergic rhinitis should control these symptoms without adversely affecting daily activities or cognitive performance and should prevent sequelae such as asthma exacerbation or sinusitis. This review describes a stepwise approach to treatment of allergic rhinitis derived from a synthesis of clinical trial results, patient preferences, and real-world tolerability data. Key clinical considerations include frequency and intensity of symptoms, patient age, comorbidities, compliance with treatment regimens (influenced by formulation, route and frequency of administration), and effects on quality of life. Oral second-generation antihistamines, versus first-generation agents and inhaled corticosteroids, should be considered first-line treatment because they provide rapid relief of most allergic rhinitis symptoms without safety and tolerability issues. Additional therapeutic agents can then be added or substituted based on individual symptom response.

Effects of fexofenadine hydrochloride in a guinea pig model of antigen-induced rhinitis

Allergic rhinitis is an inflammatory disease of the nasal mucosa, induced by histamine, leukotrienes, and other substances released from mast cells. Fexofenadine hydrochloride, the active metabolite of terfenadine, is a novel, nonsedating antiallergic drug having H1 receptor antagonistic activity. Fexofenadine is effective for the treatment of allergic rhinitis. However, its mechanism of action in attenuating nasal congestion has not yet been elucidated. Therefore, we first examined the effects of fexofenadine on a guinea pig model of antigen-induced rhinitis. We also evaluated the effects of mepyramine, zafirlukast and ramatroban in this model; these drugs are an H1 receptor antagonist, a selective leukotriene antagonist and a selective thromboxane antagonist, respectively. Rhinitis was induced by ovalbumin (OVA) instillation into the nasal cavity of animals that had been sensitized by two earlier OVA injections (s.c. and i.p.). The nasal airway resistance was measured for 45 min after the challenge. Fexofenadine hydrochloride (20 mg/kg) and terfenadine (20 mg/kg) administered orally 70 min prior to the challenge significantly inhibited (fexofenadine, p < 0.001, terfenadine, p < 0.05) the increase in nasal airway resistance. Ramatroban (30 mg/kg) administered orally 60 min prior to the challenge also significantly inhibited (p < 0.05) the increase in nasal airway resistance. In contrast, mepyramine (3 mg/kg i.v.) and zafirlukast (3 mg/kg p.o.) failed to reduce the increase in nasal airway resistance. These results suggest that thromboxane may be involved in the increase in the nasal airway resistance in this model. Accordingly, fexofenadine may reduce the increase in nasal airway resistance by inhibiting the release of chemical mediators, including thromboxane, that are involved in the increase in nasal airway resistance in this model.

Desloratadine and levocetirizine improve nasal symptoms, airflow, and allergic inflammation in patients with perennial allergic rhinitis: a pilot study

BACKGROUND

Nasal obstruction is the main symptom in patients with perennial allergic rhinitis. Some new antihistamines have been demonstrated to be capable of improving this symptom.

OBJECTIVE

The aim of this pilot study was to evaluate nasal symptoms, nasal airflow, eosinophils, and IL-4 in patients with perennial allergic rhinitis, before and after treatment with two new antihistamines: desloratadine and levocetirizine.

METHODS

Thirty patients with perennial allergic rhinitis were evaluated, 26 males and 4 females (mean age 26+/-7.1 years). All of them received either desloratadine (5 mg/daily) or levocetirizine (5 mg/daily) or placebo for 4 weeks. The study was double-blind, parallel-group, placebo-controlled, and randomized. Total symptom score (including: rhinorrhea, nasal itching, sneezing, and nasal obstruction) was assessed before and after treatment. Rhinomanometry and decongestion test, nasal lavage, and nasal scraping were performed in all subjects before and after treatment. Eosinophils were counted by conventional staining; IL-4 was measured by immunoassay of fluids recovered from nasal lavage.

RESULTS

Desloratadine and levocetirizine treatment induced significant symptom relief and significant reduction of IL-4. Both antihistamines significantly affected all parameters in comparison with placebo.

CONCLUSIONS

This pilot study demonstrates the effectiveness of antihistaminic treatment in: i) relieving nasal symptoms, including obstruction, ii) improving nasal airflow, iii) exerting decongestant activity, iv) reducing eosinophil infiltration, and v) diminishing IL-4 levels.

Oral antihistamines for the symptom of nasal obstruction in persistent allergic rhinitis - a systematic review of randomized controlled trials

BACKGROUND

Oral antihistamines are recommended by a World Health Organisation working group as a first-line pharmacological treatment in mild persistent allergic rhinitis. There is, however, uncertainty with respect to their effectiveness for a common symptom, that of nasal obstruction.

OBJECTIVE

To test the null hypothesis that oral antihistamines have no effect on the symptom of nasal obstruction in a clinical setting in patients with persistent allergic rhinitis.

METHODS

Protocol based review of double-blind randomized controlled trials of oral antihistamine (i.e. drugs considered to act as a histamine receptor type-1 antagonist) vs. placebo. A search was carried out for published and unpublished trials. Individuals had to be age 12 years or older (with a diagnosis confirmed by skin prick tests, IgE blood tests or nasal allergen challenge), experiencing their normal allergen exposure. A symptom score for nasal obstruction had to be recorded. Predetermined quality criteria were applied. Treating their data as 4-point scores, a meta-analysis was carried out for studies, which provided enough data to be pooled.

RESULTS

Meta-analysis found a weighted mean difference of -0.52 in favour of treatment for patient-assessed symptom scores (95% confidence interval (CI)-0.73,-0.31, P<0.00001), and of -0.33 in favour of treatment for healthcare worker assessed scores (95% CI -0.49, -0.16, P = 0.0001).

CONCLUSION

Oral antihistamines cause statistically significant improvement in the symptom of nasal obstruction in patients with persistent allergic rhinitis.

Second-Generation Antihistamines

Antihistamines are useful medications for the treatment of a variety of allergic disorders. Second-generation antihistamines avidly and selectively bind to peripheral histamine H1 receptors and, consequently, provide gratifying relief of histamine-mediated symptoms in a majority of atopic patients. This tight receptor specificity additionally leads to few effects on other neuronal or hormonal systems, with the result that adverse effects associated with these medications, with the exception of noticeable sedation in about 10% of cetirizine-treated patients, resemble those of placebo overall. Similarly, serious adverse drug reactions and interactions are uncommon with these medicines. Therapeutic interchange to one of the available second-generation antihistamines is a reasonable approach to limiting an institutional formulary, and adoption of such a policy has proven capable of creating substantial cost savings. Differences in overall efficacy and safety between available second-generation antihistamines, when administered in equivalent dosages, are not large. However, among the antihistamines presently available, fexofenadine may offer the best overall balance of effectiveness and safety, and this agent is an appropriate selection for initial or switch therapy for most patients with mild or moderate allergic symptoms. Cetirizine is the most potent antihistamine available and has been subjected to more clinical study than any other. This agent is appropriate for patients proven unresponsive to other antihistamines and for those with the most severe symptoms who might benefit from antihistamine treatment of the highest potency that can be dose-titrated up to maximal intensity.

Levocetirizine improves nasal obstruction and modulates cytokine pattern in patients with seasonal allergic rhinitis: a pilot study

BACKGROUND

Allergic rhinitis is characterized by an IgE-dependent inflammation. Nasal obstruction is related to allergic inflammation. Some antihistamines have been demonstrated to be capable of improving this nasal symptom.

OBJECTIVE

The aim of this pilot study was to evaluate nasal symptoms, nasal airflow, inflammatory cells, and cytokine pattern in patients with seasonal allergic rhinitis (SAR), before and after treatment with levocetirizine, desloratadine, or placebo.

METHODS

Thirty patients with SAR were evaluated, 27 males and three females (mean age 26.9+/-5.4 years). All of them received levocetirizine (5 mg/day), desloratadine (5 mg/day), or placebo for 2 weeks. The study was double-blind, parallel-group, placebo-controlled, and randomized. Total symptom score (TSS) (including: rhinorrhea, nasal itching, sneezing, and nasal obstruction) was assessed before and after treatment. Rhinomanometry, nasal lavage, and nasal scraping were performed in all subjects before and after treatment. Inflammatory cells were counted by conventional staining; IL-4 and IL-8 were measured by immunoassay on fluids recovered from nasal lavage.

RESULTS

Levocetirizine treatment induced significant symptom relief (P=0.0009) and improved nasal airflow (P=0.038). Desloratadine also relieved TSS (P=0.01), but did not affect nasal airflow. Levocetirizine significantly reduced eosinophils (P=0.029), neutrophils (P=0.005), IL-4 (P=0.041), and IL-8 (P=0.02), whereas desloratadine diminished IL-4 only (P=0.044). Placebo treatment did not significantly affect any evaluated parameters.

CONCLUSIONS

This pilot study demonstrates the effectiveness of levocetirizine in: (i) relieving nasal symptoms, (ii) improving nasal airflow, (iii) reducing leucocyte infiltration, and (iv) diminishing cytokine levels. These findings are the first evidence of the effectiveness of levocetirizine in SAR.

The effect of budesonide on the cytokine pattern in patients with perennial allergic rhinitis

BACKGROUND

A T(H)2-polarized cytokine pattern has been demonstrated in allergic rhinitis. Budesonide represents an effective topical corticosteroid in the management of allergic rhinitis.

OBJECTIVE

To evaluate cytokine pattern and symptoms in patients with perennial allergic rhinitis before and after treatment with intranasal budesonide.

METHODS

All patients received budesonide aqueous nasal spray or placebo for 2 weeks. The study was double-blind, parallel group, placebo controlled, and randomized. Nasal lavage was performed in all patients before and after treatment. A panel of cytokines, including interleukin 4 (IL-4), IL-5, and IL-6, was measured by immunoassay on fluids recovered from nasal lavage. Total symptom score (including rhinorrhea, nasal itching, sneezing, and nasal obstruction) was evaluated before and after treatment.

RESULTS

Twenty patients with perennial allergic rhinitis were evaluated (13 men and 7 women; mean age, 24.7 years). Budesonide aqueous nasal spray treatment showed a significant decrease of IL-4 (P = .007), IL-5 (P = .04), and IL-6 levels (P = .009). Budesonide aqueous nasal spray treatment also induced significant symptom relief (P = .006). Placebo treatment did not significantly affect the evaluated parameters.

CONCLUSIONS

This study shows that budesonide aqueous nasal spray is effective in exerting immunomodulatory activity by reducing cytokine pattern and relieving symptoms. These findings are evidence of the effects of intranasal budesonide in treating perennial allergic rhinitis.

Effect of the second-generation antihistamine, fexofenadine, on cough reflex sensitivity and pulmonary function

AIMS

Current guidelines recommend the use of first-generation antihistamines for the treatment of cough due to rhinitis/postnasal drip syndrome. The antitussive activity of the second-generation antihistamine, fexofenadine, has not been investigated. Therefore, we evaluated the effect of fexofenadine on capsaicin-induced cough in healthy volunteers and in subjects with acute viral upper respiratory tract infection (URI).

METHODS

Twelve healthy volunteers and 12 subjects with URI underwent pulmonary function testing and capsaicin cough challenge on two separate days, 2 h after ingesting 180 mg fexofenadine or matched placebo. Subjects inhaled single, vital-capacity breaths of capsaicin aerosol, administered in incremental doubling concentrations, until the concentration inducing five or more coughs (C5) was determined.

RESULTS

In both subject groups, C5 was not significantly different after fexofenadine compared to placebo. In subjects with URI, pulmonary function studies were also similar. In healthy volunteers, however, FEV1 and FEF(25-75), pulmonary function parameters reflecting the degree of airway dilatation, were significantly increased after fexofenadine. Mean (95% CI) values for FEV1(L) after fexofenadine and placebo were 3.16 (2.77, 3.55) and 3.08 (2.69, 3.47), respectively (P = 0.017). Mean values for FEF(25-75)(L/s) were 3.49 (3.10, 3.88) and 3.26 (2.79, 3.72), respectively (P = 0.029).

CONCLUSIONS

Fexofenadine demonstrated no antitussive activity against capsaicin-induced cough in healthy volunteers and subjects with URI. The ineffectiveness of fexofenadine in suppressing cough probably reflects the lack of anticholinergic activity and central nervous system penetrance that is characteristic of first-generation antihistamines. The mild bronchodilation induced by fexofenadine in healthy volunteers is of unclear clinical significance and requires further investigation.

A single-center, randomized, double-blind, placebo-controlled, crossover investigation of the effects of fexofenadine hydrochloride 180 mg alone and with alcohol, with hydroxyzine hydrochloride 50 mg as a positive internal control, on aspects of cognitive and psychomotor function related to driving a car

BACKGROUND

Antihistamines (H(1)-receptor antagonists) are the mainstay of symptomatic therapy for allergic disorders. Antihistamines are needed that cause no disruptive effects on cognitive and psychomotor function. It is essential that antihistamines maintain the integrity of the cognitive system, not only in ambulatory patients at increased risk of drug-induced traffic- or work-related accidents, but also in students and others whose cognitive or intellectual impairment may adversely affect their performance.Objective; The goal of this study was to investigate the acute effects of fexofenadine hydrochloride 180 mg, alone and with a "social" dose of alcohol, on subjective feelings of sedation and on a battery of objective measures related to driving a car. These measures included information processing, psychomotor speed, and reaction time in an on-the-road car-driving task. Hydroxyzine hydrochloride 50 mg was included in the study as a positive internal control to validate the sensitivity of the psychometri tests to nonspecific impairment.

METHODS

In this randomized, double-blind, 6-way, crossover study conducted at the Human Psychopharmacology Research Unit, Medical Research Centre (University of Surrey, Guildford, United Kingdom), 18 healthy volunteers received fexofenadine 180 mg, hydroxyzine 50 mg, and placebo alone and with alcohol (0.3 g/kg body weight or approximately 0.43-0.50 g/L blood-alcohol concentration). Treatment periods were separated by a washout period of at least 6 days. Subjects performed tests of cognitive and psychomotor performance at 1, 3, and 5 and hours after dosing. The test battery included subjective ratings of sedation, critical flicker fusion (CFF), choice reaction time (including recognition reaction time [RRT], motor reaction time [MRT], total reaction time [TRT], and brake reaction time [BRT].

RESULTS

Eighteen healthy male volunteers (median age, 30.5 years [range, 23-44 years]) were entered into the study. Fexofenadine alone and with alcohol had no significant effect on performance compared with placebo and was not distinguishable from placebo in any of the objective or subjective tests at any point. However, impairment was evident following the administration of hydroxyzine. Hydroxyzine caused significant impairment in CFF (P < 0.05), RRT (P < 0.001), and TRT (P < 0.001) compared with placebo. Hydroxyzine with alcohol significantly disrupted performance on all of the above measures with respect to both placebo and fexofenadine (P < 0.05) as well as MRT (P < 0.001). No significant treatment effects on BRT were found.

CONCLUSION

Fexofenadine 180 mg did not have disruptive effects on objective measures related to driving a car and aspects of psychomotor and cognitive function, even when combined with a dose of alcohol equivalent to 0.3 g/kg body weight, in a study in which the psychometric assessments were shown to be sensitive to impairment.

Efficacy and safety of desloratadine in the treatment of perennial allergic rhinitis

BACKGROUND

The evidence base for the use of H1-antihistamines in the treatment of perennial allergic rhinitis is considerably smaller than it is in the treatment of seasonal allergic rhinitis.

OBJECTIVE

We hypothesized that desloratadine, a new, nonsedating selective H1-antihistamine, would be efficacious and safe in the treatment of perennial allergic rhinitis.

METHODS

In a multicenter, randomized, placebo-controlled, double-blind, parallel-group study, 676 patients with symptomatic perennial allergic rhinitis were randomly assigned to 4 weeks of treatment with either 5 mg of desloratadine once daily or placebo. Efficacy was assessed by using a morning-evening instantaneous total symptom score (TSS), which was composed of scores for 4 individual nasal symptoms (rhinorrhea, itching, sneezing, and postnasal drip) and 3 individual nonnasal symptoms (itching eyes, watering eyes, and itching of the ears or palate). Secondary outcome measures included a morning-evening reflective TSS, total nasal and nonnasal symptoms scores, and individual symptom scores. Safety evaluations, including 12-lead electrocardiograms, were performed.

RESULTS

Six hundred thirty-four patients completed the study. Desloratadine consistently diminished perennial allergic rhinitis symptoms, reducing the morning-evening instantaneous TSS (P =.005), the morning-evening reflective TSS (P =.007), the morning-evening reflective total nonnasal score (P =.023), and the individual nasal symptom scores for rhinorrhea, nasal itching, sneezing, and postnasal drip/drainage (P =.05 to P =.013) during weeks 1 through 4. Improvement in symptoms was observed after the first dose. Dropouts, and the type and frequency of adverse events (headache, viral infection, pharyngitis, and upper respiratory tract infection), were similar in both treatment groups. No clinically significant changes in QTc intervals were observed.

CONCLUSIONS

Desloratadine rapidly and safely reduced the symptoms of perennial allergic rhinitis, and its efficacy did not diminish during 4 weeks of treatment.

Effect of fexofenadine hydrochloride on cedar pollinosis

OBJECTIVE

To investigate the therapeutic efficacy of fexofenadine hydrochloride (Allegra(R) tablets), an antihistaminic launched in 2001, in patients with cedar pollinosis by dividing them into two groups for comparison, i.e. the early-treatment group in which treatment was started before the initial day of the pollen scattering, and the therapeutic-treatment group in which treatment was started after the initial day of the pollen scattering.

METHODS

Early-treatment group: patients who visited the hospital before the initial day of cedar pollen scattering were orally given one tablet of the drug twice daily. Therapeutic-treatment group: patients who visited the hospital after the initial day of cedar pollen scattering were orally given one tablet of the drug twice daily. The total number of cases in which the efficacy evaluation was possible was 37 cases (19 cases of the early-treatment group and 18 cases of the therapeutic-treatment group) after application of exclusion criteria.

RESULTS

The useful rate of moderately effective or better against sneeze was 90% in the early-treatment group, and 78% in the therapeutic-treatment group, and there was a significant difference between both groups. The degree of satisfaction in the early-treatment group was 3.8 points, and 4.2 points in the therapeutic-treatment group, and the therapeutic-treatment group showed a higher score, but there was no significant difference between both groups. As adverse reaction, there was only one case of mild dizziness (2.7%), and no other adverse reactions such as sleepiness were observed.

CONCLUSIONS

It was suggested that fexofenadine hydrochloride administered in patients with cedar pollinosis from before substantial pollen scattering might control their symptoms to mild ones, and might control worsening of their symptoms after the substantial pollen scattering, and, therefore, the drug was considered to be useful in early therapy.

Novel approaches in the treatment of allergic rhinitis

PURPOSE OF REVIEW

The increasing prevalence of allergic rhinitis, its impact on individual quality of life and social costs, as well as its role as a risk factor for asthma, underline the need for improved treatment options for this disorder. We reviewed the recent literature published in English, dealing with relevant and appropriately controlled clinical trials on the treatment of allergic rhinitis.

RECENT FINDINGS

In addition to well established pharmacological therapies with antihistamines, corticosteroids, decongestants and mast cell stabilizers, new therapeutic options become increasingly important, including leukotriene modifiers, anti-immunoglobulin E antibodies, phosphodiesterase inhibitors and intranasal heparin; there also exist new developments in appropriate allergen specific immunotherapy.

SUMMARY

Promising results, both with established and novel treatment options, are communicated, but further studies are still necessary to confirm these data.

Treatment of allergic rhinitis

Allergic rhinitis, a common and often debilitating disease marked by rhinorrhea, nasal congestion, nasal itching, and sneezing, is on the increase worldwide. Treatment involves allergen avoidance, pharmacotherapy, and, in selected cases, immunotherapy. This overview describes the characteristics, pathogenesis, and diagnosis of allergic rhinitis. The major contributing allergens of seasonal and perennial allergic rhinitis are identified. Pharmacotherapy is described within the context of treatment guidelines developed by the major asthma and allergy professional organizations. Oral H1 antihistamines are first-line therapy for mild-to-moderate allergic rhinitis. The newer, nonsedating agents are recommended over first-generation antihistamines. Some of the newer oral antihistamines, such as cetirizine, desloratadine, and fexofenadine, have been shown to relieve the symptom of nasal congestion. Intranasal steroids are first-line therapy for patients with more severe symptoms.

Effects of fexofenadine and desloratadine on subjective and objective measures of nasal congestion in seasonal allergic rhinitis

BACKGROUND

In vitro studies have shown much higher H1-receptor antagonist potency with desloratadine (DL) compared to fexofenadine (FEX), although it is unclear whether this has any clinical relevance on disease control parameters in seasonal allergic rhinitis (SAR), especially for nasal congestion.

OBJECTIVE

To compare the relative efficacy between presently recommended doses of DL and FEX on daily measurements of peak nasal inspiratory flow (PNIF) and nasal symptoms in SAR.

METHODS

Forty-nine patients with SAR were randomized into a double-blind, placebo-controlled cross-over study during the grass pollen season, comparing 2 weeks of once daily treatment with (a) 180 mg FEX or (b) 5 mg DL, taken in the morning. There was a 7-10 day placebo run-in and washout prior to each randomized treatment. Measurements were made in the morning (AM) and in the evening (PM) for PNIF (the primary outcome variable), nasal and eye symptoms. The average of AM/PM values were used for analysis.

RESULTS

There were significant (P < 0.05) improvements, compared to placebo, with FEX and DL, for PNIF, nasal blockage, nasal irritation, and total nasal symptoms, but not nasal discharge or eye symptoms. There were no significant differences between active treatments. Values for PNIF (L/min) for mean placebo baseline, mean difference from baseline (95% CI for difference) were 126, 10 (4-16) for FEX; and 122, 11 (4-17) for DL. The mean difference (95% CI) between FEX vs. DL was 1 L/min (-7-8). Values for total nasal symptoms (out of 12) were: 3.2, 0.7 (0.2-1.2) for FEX; and 3.4, 0.9 (0.3-1.5) for DL, and for nasal blockage (out of 3) were: 1.1, 0.2 (0.1-0.4) for FEX; and 1.2, 0.3 (0.1-0.5) for DL. The mean difference (95% CI) in total nasal symptoms and nasal blockage between FEX vs. DL was 0.1 (-0.6-0.8) and 0.1 (-0.2-0.3), respectively.

CONCLUSIONS

Recommended once daily doses of fexofenadine and desloratadine were equally effective in improving nasal peak flow and nasal symptoms in SAR.

Emerging safety issues regarding long-term usage of H(1)receptor antagonists

The second generation histamine H(1)-receptor antagonists are important therapeutic tools in the treatment of atopic disease and may also have a place as an adjunct therapy for those patients whose allergic asthma coexists with allergic rhinitis. They are amongst the most widely prescribed and safest drugs in the world. However, as second generation H(1)-receptor antagonists are used to treat non-life threatening conditions, the risk of adverse effects is of vital importance. For many, the potential for sedation by some of the newer antihistamines still remains an issue, while there have recently been widespread concerns regarding the potential for cardiotoxicity and the impact of drug-drug interactions associated with some second generation H(1)-receptor antagonists. Consequently, progress with this class of drugs should involve not only increased efficacy but also improvements in their safety and specificity. Moreover, there is a trend towards using second generation H(1)-receptor antagonists as long-term therapy rather than confining their use to treating the short-term manifestations of allergic disease. To this end, a number of novel, potent and safe antihistamines have been developed which are either metabolites of active drugs or enantiomers. This review will examine some of the safety issues associated with established and newer second generation drugs particularly in relation to their long-term usage in adults and children.