Loratadine and desethoxylcarbonyl-loratadine inhibit the immunological release of mediators from human FcɛRI+cells

Oral isotretinoin with desloratadine compared with oral isotretinoin alone in the treatment of moderate to severe acne: a randomized, assessor-blinded study

BACKGROUND

Our aim was to measure the effectiveness of oral isotretinoin with desloratadine compared with oral isotretinoin alone in treating moderate to severe acne at a tertiary care teaching hospital in North India. In this study, 90 patients with moderate to severe acne were enrolled to participate based on their fulfilling the inclusion criteria.

METHODS

A randomized, assessor-blinded, parallel-arm study was conducted. Randomization was done using computer-generated tables to allocate treatments in a 1:1 ratio. A low-dose oral isotretinoin at a dose of 0.3 mg/kg/day with tab desloratadine at 5 mg/day was applied to the study group and compared against the same patients going without the dosage when controls were conducted. Follow-up was at 4, 8, and 12 weeks.

RESULTS

The primary outcome was an improved global acne grading system (GAGS) score and decreased acne lesion count.

SECONDARY OUTCOME

patient satisfaction with treatment. The 90 participants were randomized and 15 participants dropped out of the study, leaving 75 participants for intention to treat analysis (n = 41, n = 30). At week 12, the GAGS score and acne lesion count between the study and control groups were comparable (P > 0.05). Pruritus reported was 9.76% in the study versus 33.33% in the control group (P = 0.018). Also, 53.66% of participants reported "excellent" treatment satisfaction in the study group versus 36.67% in the control group.

CONCLUSIONS

The addition of desloratadine to an isotretinoin regimen has a role in reducing disease and therapy-related pruritus in acne and leads to improved patient satisfaction.

Human Lung Mast Cells: Therapeutic Implications in Asthma

Mast cells are strategically located in different compartments of the lung in asthmatic patients. These cells are widely recognized as central effectors and immunomodulators in different asthma phenotypes. Mast cell mediators activate a wide spectrum of cells of the innate and adaptive immune system during airway inflammation. Moreover, these cells modulate the activities of several structural cells (i.e., fibroblasts, airway smooth muscle cells, bronchial epithelial and goblet cells, and endothelial cells) in the human lung. These findings indicate that lung mast cells and their mediators significantly contribute to the immune induction of airway remodeling in severe asthma. Therapies targeting mast cell mediators and/or their receptors, including monoclonal antibodies targeting IgE, IL-4/IL-13, IL-5/IL-5Rα, IL-4Rα, TSLP, and IL-33, have been found safe and effective in the treatment of different phenotypes of asthma. Moreover, agonists of inhibitory receptors expressed by human mast cells (Siglec-8, Siglec-6) are under investigation for asthma treatment. Increasing evidence suggests that different approaches to depleting mast cells show promising results in severe asthma treatment. Novel treatments targeting mast cells can presumably change the course of the disease and induce drug-free remission in bronchial asthma. Here, we provide an overview of current and promising treatments for asthma that directly or indirectly target lung mast cells.

Combination of ultra-low-dose isotretinoin and antihistamines in treating Morbihan disease - a new long-term approach with excellent results and a minimum of side effects

Morbihan disease is characterized by erythema and solid edema in the two upper thirds of the face. Underlying factors are an imbalance in lymphatic drainage, chronic inflammation, and mast cells leading to fibrosis. Treatment options known thus far have led to unsatisfactory results and have often been associated with a greater risk of side effects; even invasive options have been applied. This study presents four patients treated with a combination of ultra-low-dose isotretinoin and antihistamines for a mean duration of 14 months. While no side effects other than dryness of the lips were noted, a significant reduction of the erythema and edema could be observed in all patients. Specialists evaluated the treatment's success by photodocumentation and measured a 91.5% alleviation of erythema, and 85% reduction of edema, respectively. Based on these results, this new regimen in the therapeutic approach toward Morbihan disease is suggested due to its anti-inflammatory features and low risk of side effects.

Mast cell-neural interactions contribute to pain and itch

Mast cells are best recognized for their role in allergy and anaphylaxis, but increasing evidence supports their role in neurogenic inflammation leading to pain and itch. Mast cells act as a "power house" by releasing algogenic and pruritogenic mediators, which initiate a reciprocal communication with specific nociceptors on sensory nerve fibers. Consequently, nerve fibers release inflammatory and vasoactive neuropeptides, which in turn activate mast cells in a feedback mechanism, thus promoting a vicious cycle of mast cell and nociceptor activation leading to neurogenic inflammation and pain/pruritus. Mechanisms underlying mast cell differentiation, activation, and intercellular interactions with inflammatory, vascular, and neural systems are deeply influenced by their microenvironment, imparting enormous heterogeneity and complexity in understanding their contribution to pain and pruritus. Neurogenic inflammation is central to both pain and pruritus, but specific mediators released by mast cells to promote this process may vary depending upon their location, stimuli, underlying pathology, gender, and species. Therefore, in this review, we present the contribution of mast cells in pathological conditions, including distressing pruritus exacerbated by psychologic stress and experienced by the majority of patients with psoriasis and atopic dermatitis and in different pain syndromes due to mastocytosis, sickle cell disease, and cancer.

Human mast cells and basophils-How are they similar how are they different?

Mast cells and basophils are key contributors to allergies and other inflammatory diseases since they are the most prominent source of histamine as well as numerous additional inflammatory mediators which drive inflammatory responses. However, a closer understanding of their precise roles in allergies and other pathological conditions has been marred by the considerable heterogeneity that these cells display, not only between mast cells and basophils themselves but also across different tissue locations and species. While both cell types share the ability to rapidly degranulate and release histamine following high-affinity IgE receptor cross-linking, they differ markedly in their ability to either react to other stimuli, generate inflammatory eicosanoids or release immunomodulating cytokines and chemokines. Furthermore, these cells display considerable pharmacological heterogeneity which has stifled attempts to develop more effective anti-allergic therapies. Mast cell- and basophil-specific transcriptional profiling, at rest and after activation by innate and adaptive stimuli, may help to unravel the degree to which these cells differ and facilitate a clearer understanding of their biological functions and how these could be targeted by new therapies.

Association Between Migraine and Atopic Diseases in Childhood: A Potential Protective Role of Anti-Allergic Drugs

BACKGROUND

Migraine is a common cause of headache in childhood. Several studies have investigated the association between migraine and atopic diseases, mostly in the adult population.

OBJECTIVE

This study aimed to investigate this association in children.

METHODS

A case-control study was conducted across 3 European tertiary care hospitals between June 2014 and August 2014. Cases (n = 229) were children aged 6-18 years consulting for a migraine episode. Controls in the same age range (n = 406) were consulting for a minor injury and did not have a history of recurrent headache. Logistic regression analyses tested the effect of atopic diseases and anti-allergic therapies on occurrence of migraine.

RESULTS

Children with migraine were more likely to have persistent asthma compared to absence of asthma (odds ratio [OR]: 4.57, 95% confidence interval [CI]: 2.04-10.24) and less likely to have been treated by inhaled or nasal corticosteroid (OR: 0.34, 95% CI: 0.15-0.76) or antihistamine therapy (OR: 0.33, 95% CI: 0.18-0.60). The median number of monthly migraine episodes was higher in children with persistent asthma (3; interquartile [IQR]: 1-4; range: 0.5-10) compared to children with intermittent asthma (2; IQR: 1-3; range: 0.1-4) or non-asthmatic children (2; IQR: 1-3; range: 0.1-12) (P < .01).

CONCLUSION

Persistent childhood asthma was associated with increased risk of migraine and higher frequency of migraine attacks. History of anti-asthmatic or anti-allergic therapies was associated with decreased risk of migraine in children and adolescents. The role of these therapies on the pathogenesis and occurrence of migraine needs to be further elucidated because of the huge potential impact in terms of public health.

The role of antihistamines in chronic actinic dermatitis treatment

Inveterate actinic dermatitis is an immunologically mediated photodermatosis characterized by itchy eczematous dermhelminthiasis exposed to sunlight. The disease proceeds in the same way as the atopic eczema or atopic dermatitis. The treatment of patients with inveterate actinic dermatitis is similar to the treatment of patients with atopic dermatitis and eczema. Administration of the modern antihistaminic preparation desloratadine (Aerius) in the treatment has a positive effect on the skin process relief and on some cellular and humoral immunity factors.

A novel model of IgE-mediated passive pulmonary anaphylaxis in rats

Mast cells are central effector cells in allergic asthma and are augmented in the airways of asthma patients. Attenuating mast cell degranulation and with it the early asthmatic response is an important intervention point to inhibit bronchoconstriction, plasma exudation and tissue oedema formation. To validate the efficacy of novel pharmacological interventions, appropriate and practicable in vivo models reflecting mast cell-dependent mechanisms in the lung, are missing. Thus, we developed a novel model of passive pulmonary anaphylaxis in rats. Rats were passively sensitized by concurrent intratracheal and intradermal (ear) application of an anti-DNP IgE antibody. Intravenous application of the antigen, DNP-BSA in combination with Evans blue dye, led to mast cell degranulation in both tissues. Quantification of mast cell degranulation in the lung was determined by (1) mediator release into bronchoalveolar lavage, (2) extravasation of Evans blue dye into tracheal and bronchial lung tissue and (3) invasive measurement of antigen-induced bronchoconstriction. Quantification of mast cell degranulation in the ear was determined by extravasation of Evans blue dye into ear tissue. We pharmacologically validated our model using the SYK inhibitor Fostamatinib, the H₁-receptor antagonist Desloratadine, the mast cell stabilizer disodium cromoglycate (DSCG) and the β₂-adrenergic receptor agonist Formoterol. Fostamatinib was equally efficacious in lung and ear. Desloratadine effectively inhibited bronchoconstriction and ear vascular leakage, but was less effective against pulmonary vascular leakage, perhaps reflecting the differing roles for histamine receptor sub-types. DSCG attenuated both vascular leakage in the lung and bronchoconstriction, but with a very short duration of action. As an inhaled approach, Formoterol was more effective in the lung than in the ear. This model of passive pulmonary anaphylaxis provides a tissue relevant readout of early mast cell activity and pharmacological benchmarking broadly reflects responses observed in patients with asthma.

Immunopharmacological modulation of mast cells

Mast cells produce a wide spectrum of mediators and they have been implicated in several physiopathological conditions (e.g. allergic reactions and certain tumors). Pharmacologic agents that modulate the release of mediators from mast cells has helped to elucidate the biochemical mechanisms by which immunological and non-immunological stimuli activate these cells. Furthermore, the study of surface receptors and signaling pathways associated with mast cell activation revealed novel pharmacologic targets. Thus, the development of pharmacologic agents based on this new wave of knowledge holds promise for the treatment of several mast cell-mediated disorders.

Effect of antihistamine as an adjuvant treatment of isotretinoin in acne: a randomized, controlled comparative study

BACKGROUND

Isotretinoin has been frequently used for acne therapy. However, it has limitation in acceptance because of its adverse effects. Although antihistamine recently revealed to decrease the lipogenesis, evidence is lacking regarding the clinical relevance of antihistamine in the treatment of acne.

OBJECTIVES

To evaluate the clinical efficacy and tolerability of antihistamine as an adjuvant treatment of isotretinoin.

METHODS

Forty patients with moderate acne were included in this randomized, controlled comparative study. Twenty patients were treated with isotretinoin and 20 patients were treated with additional antihistamine, desloratadine. Assessment was made at baseline, after 2, 4, 8 and 12 weeks of treatment.

RESULTS

At week 12, compared with isotretinoin only group, isotretinoin with additional antihistamine group showed more statistically significant decrease in acne lesion counts (non-inflammatory lesions: 44.8% vs. 17.8%; inflammatory lesions: 55.8% vs. 22.9%; total lesions: 45.6% vs. 18.7%; all P < 0.05). Significant decrease was also observed in the score of global acne grading system and the measured value of sebum and erythema. Moreover, acne flare during the treatment occurred less frequently and adverse events of isotretinoin were more tolerable in additional antihistamine group.

CONCLUSIONS

This results provide early evidence that antihistamine has a synergic effect with minimizing the side-effect of isotretinoin, and may be used as an adjuvant treatment of moderate acne.

Safety evaluation of desloratadine in allergic rhinitis

INTRODUCTION

Desloratadine is a biologically active metabolite of second-generation antihistamine loratadine. It is also indicated for the treatment of allergic diseases, including allergic rhinitis.

AREAS COVERED

A Medline search was conducted to identify preclinical and clinical studies of desloratadine. This was supplemented with additional articles obtained from online sources. The focus of this review is on the safety profile of desloratadine.

EXPERT OPINION

The review of these data indicates that the safety profile of desloratadine is similar to other second-generation antihistamines. Desloratadine is highly selective for histamine H₁-receptors, does not cross the blood-brain barrier (BBB), and has minimal adverse events (very low sedation rate), with a better safety and tolerability than first-generation antihistamines. Desloratadine is safe and well tolerated without having central nervous system (CNS) or cardiovascular effects and with low drug interaction.

Predicting and establishing the clinical efficacy of a histamine h(1)-receptor antagonist : desloratadine, the model paradigm

Antihistamines are well established as a mainstay for treating allergic diseases, including seasonal and perennial allergic rhinitis as well as other conditions, such as chronic idiopathic urticaria. The development of new antihistamines is a multistage process that includes in vitro and in vivo assessments of the antihistaminic, anti-inflammatory and antiallergic properties of new therapies. Results of these assessments are critical for predicting and establishing the clinical efficacy of an antihistamine. The focus of this article is to review the investigational methods used to assess the efficacy, safety and tolerability of newer histamine H(1)-receptor antagonists. Desloratadine, a new-generation H(1)-receptor antagonist, was chosen to illustrate the use of this model paradigm. Data obtained from two large observational studies are presented, confirming results obtained from clinical trials that the in vitro inhibition of release of inflammatory mediators such as histamine, prostaglandins, leukotrienes and the reduction of secretion of cytokines such as IL-4 and IL-13 at physiological concentrations is reflected in increased efficacy, particularly upon nasal obstruction. A recent discovery that des- loratadine inhibits nuclear factor-kappaB may be the underlying explanation for much of this extra anti-inflammatory activity.

Antihistaminic, anti-inflammatory, and antiallergic properties of the nonsedating second-generation antihistamine desloratadine: a review of the evidence

The allergy cascade presents widespread inflammatory and proinflammatory activation, robust cytokine and chemokine signaling, and heterogeneous immune and endothelial responses that lead ultimately to the manifestations of allergic reaction. Histamine, a small peptide with inherent vasoactive properties, is released from granules contained within mast cells, basophils, lymphocytes, and other reservoirs and interacts with histamine receptors to regulate numerous cellular functions involved in allergic inflammation and immune modulation. Of the known histamine receptors, the H(1)-receptor is most clearly associated with potentiation of proinflammatory immune cell activity and enhanced effector function and is the prime focus of suppressive therapy. Second-generation oral H(1)-antihistamines, such as cetirizine, desloratadine, fexofenadine, levocetirizine, and loratadine, are mainstays of allergy treatment, acting as highly specific, long-acting H(1)-receptor agonists at its unique receptor. The ongoing identification of immune effector cells and mediators involved in the allergic cascade indicates that further research is necessary to define the role of antihistamines such as desloratadine in anti-inflammatory therapy.

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.

Inhibition of cold urticaria by desloratadine

INTRODUCTION

The effect of 5 mg desloratadine for 4 days was tested with ice-cubes before and after 4 days of treatment in 12 patients with cold urticaria. They had been asked not to take any antihistamine for at least 4 days.

OBJECTIVE

To find the effect of desloratadine on wheals and itching induced by cold.

METHOD

Ice-cubes in a thin plastic foil were placed on the inside of forearms for 0.5 to12 minutes. The time needed to produce a confluent urticaria, four or more small wheals and fewer than four small wheals were registered, together with the degree of itching.

RESULTS

Before treatment a mean of 6.2 minutes was needed to cause a confluent urticaria, and itching occurred in seven of the patients. Four or more small wheals were observed after a mean of 3.7 minutes and fewer than four after a mean of 1.2 minutes. One 5 mg tablet of desloratadine was then given each morning for 4 days and the ice-cube test was repeated 4-5 hours after the last dose: no confluent urticaria and no itching occurred in any of the patients. Four or more small wheals were seen in two patients after 12 minutes, but there was no such reaction in the other 10 patients; in seven patients one to three small wheals developed. After 2-3 months of continued treatment four patients had noticed some wheals when out in the cold, but no itching. The symptoms of one patient with a delayed reaction after exposure to cold disappeared totally after a dose increase to 10 mg.

CONCLUSION

Desloratadine markedly inhibited the reactions to cold induced urticaria.

The effects of the nasal antihistamines olopatadine and azelastine in nasal allergen provocation

BACKGROUND

Olopatadine, an antihistamine used in allergic conjunctivitis, is under development as a nasal preparation for the treatment of allergic rhinitis.

OBJECTIVES

To evaluate the efficacy of olopatadine in suppressing symptoms and biomarkers of the immediate reaction induced by nasal allergen provocation and to compare olopatadine with azelastine in the same model.

METHODS

The study was approved by the Johns Hopkins University institutional review board, and all subjects gave written consent. We studied 20 asymptomatic subjects with seasonal allergic rhinitis. The study had 2 randomized, double-blind, placebo-controlled, crossover phases that evaluated 2 concentrations of olopatadine, 0.1% and 0.2%. In a third exploratory phase, olopatadine, 0.1%, was compared with topical azelastine, 0.1%, in a patient-masked design. Efficacy variables were the allergen-induced sneezes, other clinical symptoms, and the levels of histamine, tryptase, albumin, lysozyme, and cysteinyl-leukotrienes (third study only) in nasal lavage fluids.

RESULTS

Both concentrations of olopatadine produced significant inhibition of all nasal symptoms, compared with placebo. Olopatadine, 0.1%, inhibited lysozyme levels, but olopatadine, 0.2%, inhibited histamine, albumin, and lysozyme. The effects of olopatadine, 0.1%, were comparable to those of azelastine, 0.1%.

CONCLUSIONS

Olopatadine, at 0.1% and 0.2% concentrations, was effective in suppressing allergen-induced nasal symptoms. At 0.2%, olopatadine provided evidence suggestive of inhibition of mast cell degranulation.

Interaction of loratadine with serum albumins studied by fluorescence quenching method

The interactions between loratadine and bovine serum albumin (BSA) and human serum albumin (HSA) were studied using tryptophan fluorescence quenching method. The fluorescence intensity of the two serum albumins could be quenched 70% at the molar ratio [loratadine]:[BSA (or HSA)]=10:1. In the linear range (0-50 micromol L(-1)) quenching constants were calculated using Stern-Volmer equation. Temperature in the range 298 K-310 K had a significant effect (p<0.05) on the two serum albumins through ANOVA analysis and t-test. Furthermore the conformation changes in the interactions were studied using FTIR spectroscopy.

Rhinitis symptoms and quality of life in patients with chronic perennial rhinitis treated with desloratadine

Objective:

To evaluate the outcome and the change in quality of life of patients with chronic rhinitis after treatment with desloratadine.

Study design:

A prospective, open-label, non-blinded, non-randomised study of patients in a secondary and tertiary ENT referral centre.

Methods:

Chinese patients with chronic rhinitis were recruited. The patients were assessed by a questionnaire that included rhinitis symptoms score and SF-36 health survey components. Endoscopic assessment was performed with a rigid nasoendoscope and scored according to the modified endoscopic appearance score of Lund and Kennedy. A 12-week course of desloratadine 5 mg daily was prescribed. Patients were re-evaluated after treatment. A total of 47 subjects completed the study.

Results:

There were significant reductions in median rhinitis symptoms score, from six to five (p < 0.001), and in median endoscopic appearance score, from five to three (p < 0.001). Patients' general health perception was also improved after treatment (p == 0.022).

Conclusion:

Desloratadine may be an effective treatment which provides symptomatic relief and improves the quality of life in patients with chronic rhinitis.

Urtikaria

A number of recent epidemiologic and experimental studies have enhanced our knowledge of the etiology and pathogenesis of urticaria. In addition, new instruments for diagnosing urticaria variants and for assessing the quality of life in urticaria patients have been developed. Finally, several clinical trials have demonstrated the efficacy of novel treatment approaches for urticaria, while other therapeutic concepts are under development. Here, we provide a brief review of selected findings from these recent reports and a discussion of their relevance for clinical practice.

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.

Desloratadine for chronic idiopathic urticaria: a review of clinical efficacy

Chronic idiopathic urticaria (CIU) is a disabling affliction that considerably limits patients' daily activities and interferes with sleep. Clinical studies have shown that histamine H1-receptor antagonists (antihistamines) are highly effective for inhibiting the hives/wheals and pruritus associated with CIU, as well as improving patients' quality of life. Desloratadine is a rapid-acting, once-daily, nonsedating selective H1-receptor antagonist/inverse receptor agonist with proven clinical efficacy in patients with CIU. It has 10-20 times the in vivo H1 receptor-binding affinity of loratadine, its parent compound, and 52-194 times the H1 receptor-binding affinity of cetirizine, ebastine, loratadine, and fexofenadine. Desloratadine displays linear pharmacokinetics after oral administration. Age and sex have no apparent effect on the drug's metabolism and elimination, and food does not affect its bioavailability or absorption. Desloratadine also exerts anti-inflammatory effects via mechanisms that are independent of H1-receptor antagonism. Results from randomized, double-blind, placebo-controlled studies of 6 weeks' duration in adults and adolescents with moderate-to-severe CIU indicate that desloratadine significantly minimizes the severity of pruritus, reduces the number and size of hives, and improves disease-impaired sleep and daily activities. Improvements were noted after a single dose of desloratadine and were maintained over 6 weeks of treatment. Desloratadine was safe and well tolerated in clinical trials of patients with CIU. The adverse effect profile of desloratadine in adults, as well as in children aged from 6 months to 11 years, is comparable to that of placebo. Evaluations of cognitive and psychomotor performance in adults indicate no impairment of function with dosages of desloratadine 5 mg/day. In conclusion, desloratadine is an important therapeutic option for prompt and enduring symptom relief in patients with moderate-to-severe CIU. In addition to efficacy and safety, desloratadine affords a convenient administration regimen, rapid onset of action, and an absence of drug-drug or drug-food interactions. Other important prescribing considerations are that, unlike all first-generation and some second-generation antihistamines, desloratadine is nonsedating at its clinically approved dosage and does not impair psychomotor function.

Desloratadine prevents compound 48/80-induced mast cell degranulation: visualization using a vital fluorescent dye technique

BACKGROUND

Desloratadine is a selective H1-antihistamine used in the treatment of allergic rhinitis and chronic idiopathic urticaria. Desloratadine inhibits the release of allergic inflammatory mediators in vitro. We studied the impact of desloratadine on mast cell degranulation due to activation and re-activation by the secretagogue, compound 48/80.

METHODS

Rat peritoneal eluate containing 5-6% mast cells were activated by a low concentration of compound 48/80 in a medium containing the vital fluorescent dye, Sulforhodamine-B (SFRM-B, 200 microg/ml), which is engulfed by activated mast cells. The fluorescent image of activated mast cells was captured digitally and the total fluorescent area was analyzed when desloratadine was applied before or after compound 48/80.

RESULTS

Mast cells were not activated by desloratadine (10(-4) M), SFRM-B (200 microg/ml), or diluent alone. A low concentration of compound 48/80 (0.125 microg/ml) induced fluorescence, while mast cells lost fluorescent images due to further degranulation on re-exposure to compound 48/80. Desloratadine (10(-8)-10(-4) M), inhibited compound 48/80-induced mast cell degranulation in a concentration-dependent manner. Desloratadine also reduced the loss of fluorescent images due to re-exposure to compound 48/80.

CONCLUSIONS

Desloratadine may have a mast cell stabilizing effect at low concentrations in response to repeated mast cell activation in vitro.

Role of human mast cells and basophils in bronchial asthma

Mast cells and basophils are the only cells expressing the tetrameric (alphabetagamma2) structure of the high affinity receptor for IgE (FcepsilonRI) and synthesizing histamine in humans. Human FcepsilonRI+ cells are conventionally considered primary effector cells of bronchial asthma. There is now compelling evidence that these cells differ immunologically, biochemically, and pharmacologically, which suggests that they might play distinct roles in the appearance and fluctuation of the asthma phenotype. Recent data have revealed the complexity of the involvement of human mast cells and basophils in asthma and have shed light on the control of recruitment and activation of these cells in different lung compartments. Preliminary evidence suggests that these cells might not always be detrimental in asthma but, under some circumstances, they might exert a protective effect by modulating certain aspects of innate and acquired immunity and allergic inflammation.

Inhibition of nasal polyp mast cell and eosinophil activation by desloratadine

Nasal polyp tissue which contains mast cells and eosinophils is similar to the inflamed airway mucosa in cellular composition and mediator content. This investigation assessed the effect of desloratadine (DL), on activation of cells in nasal polyp tissue. Polyps were obtained from 22 patients with chronic rhinosinusitis [nine aspirin acetylosalitic acid (ASA)-sensitive and 13 ASA-tolerant]. Polyp tissue was dispersed by digestion, and preincubated with DL and incubated with anti-immunoglobulin E (IgE) or calcium ionophore. LTC4, eosinophil cationic protein (ECP) and tryptase concentrations in supernatants were measured by immunoassays. Desloratadine (1, 10 and 50 microM) inhibited calcium ionophore-induced LTC4 release by a mean of 29%, 50% and 63% respectively, and anti-IgE-induced LTC4 release by a mean of 27%, 35% and 39% respectively. Calcium ionophore-induced tryptase release was inhibited 60% and 69% by 10 and 50 microM of DL, respectively, and anti-IgE-induced tryptase release was inhibited 33%, 47% and 66% for 1, 10 and 50 microM of DL. Desloratadine 10 microM and 50 microM inhibited ECP release by and 45% and 48% respectively. Polyp tissue from ASA-sensitive patients when compared with ASA-tolerant patients released at baseline significantly more ECP (medians 120.0 microg/ml, range: 69.0-182.0 vs 63.4 microg/ml, range: 3.7-172.0; P <0.05), but similar amounts of tryptase and LTC4. This study demonstrated that DL inhibits activation of both eosinophils and mast cells derived from a site of airway mucosal inflammation.

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.

Anti-inflammatory activity of H1-receptor antagonists: review of recent experimental research

OBJECTIVE

To compare the anti-inflammatory effects of fexofenadine with other H(1)-receptor antagonists in vitro.

DATA SOURCES

Published literature.

STUDY SELECTION

Recent experimental studies on anti-inflammatory effects of H(1)-receptor antagonists. Databases searched: Medline, Medscape.

PERIOD COVERED

1990-2003. Search terms: second-, third-generation antihistamines; sedating, nonsedating antihistamines; in vitro anti-inflammatory activity; cetirizine; ebastine; loratadine; fexofenadine; desloratadine.

RESULTS

Second- and third-generation H(1)-receptor antagonists may demonstrate significant in vitro anti-inflammatory activity at concentrations considered to be clinically relevant. In some instances, higher (supraclinical) concentrations are required to achieve comparable effects.

CONCLUSIONS

Experimental research suggests that second- and third-generation H(1)-receptor antagonists may achieve anti-inflammatory effects in a clinical context. Further studies are required to support this conclusion.

Histamine: A mediator of inflammation

Histamine and its receptors, including the recently discovered receptors (H(3) and H(4)), novel sources of histamine, and the place of histamine in mediator networks continue to be areas of great interest. The 4 major subtypes of histamine receptors, H(1) to H(4), differ in their location, second messengers, and histamine-binding characteristics. In addition, it would appear that different histamine receptor agonists and antagonists bind to different portions of the receptor complex. A fifth receptor subtype, the intracellular H(IC), has only been defined by its location within cell types that are not traditionally associated with histamine. In airway tissue, most cells express at least 1 subtype of histamine receptor; however, blockade of these receptors does not completely abolish the inflammatory response. In addition, some H(1)-antihistamines might also exert anti-inflammatory effects by pathways independent of H(1)-receptor binding. Studies of selected second-generation H(1)-antihistamines have shown that these agents inhibit the release of certain cytokines from basophils, acting at a point downstream from the calcium signaling pathway. It has not yet been determined whether this action represents a class effect.

H1-receptors: localization and role in airway physiology and in immune functions

Histamine H(1)-receptors are involved in the pathologic processes of allergy. Clinical trials of H(1)-receptor antagonists have demonstrated the efficacy of these agents in reducing the sneezing, pruritus, and rhinorrhea associated with allergic rhinitis. In the lung, H(1)-receptors mediate the bronchoconstrictive effects of histamine and increase vascular permeability, which lead to plasma exudation. H(1)-receptors are present on T cells, B cells, monocytes, and lymphocytes, and stimulation of these receptors induces pro-inflammatory effects. It has been suggested that a signal from the H(1)-receptor contributes to the antigen receptor-mediated signaling pathways that induce proliferative responses and lead to the production of cytokines and antibodies by T cells and B cells, respectively. It would appear, therefore, that the H(1)-receptor has a wider role in inflammatory processes than simply mediating the actions of histamine.

The histamine-cytokine network in allergic inflammation

Histamine is synthesized and released by human basophils, mast cells, and neurons. Its pleiotropic effects are mediated by the activation of 4 receptors: H(1), H(2), H(3), and H(4). With the advent of selective antagonists (the antihistamines widely used to treat allergic disorders), the H(1)-receptor was the first member of the receptor family to be pharmacologically defined. Increasing evidence indicates that, in addition to exerting immediate vascular and bronchial responses, histamine might modulate the immune reaction by interacting with T cells, macrophages, basophils, eosinophils, and monocytes. We have shown that, in vitro, histamine induces a concentration-dependent release of IL-6 and beta-glucuronidase from macrophages isolated from the human lung parenchyma. These effects are inhibited by fexofenadine, an H(1)-receptor antagonist, but not by ranitidine, an H(2)-receptor antagonist. This observation raises the possibility that long-term treatment with fexofenadine might have beneficial effects on immune dysregulation and tissue damage/remodeling associated with histamine-mediated macrophage activation.

Desloratadine inhibits allergen-induced airway inflammation and bronchial hyperresponsiveness and alters T-cell responses in murine models of asthma

BACKGROUND

Histamine elicits many features of immediate hypersensitivity reactions. Recent evidence indicates that H1 receptors modulate immune responses to antigens. Desloratadine (DL), a new, long-acting, H1 receptor antagonist, has both a potent antihistaminic function and anti-inflammatory properties.

OBJECTIVE

We sought to evaluate the effect of DL on allergic-airway responses in mice after inhalation of the naturally occurring aeroallergen Aspergillus fumigatus (Af ) and to examine the effects of DL on specific immune responses to a defined protein antigen with the use of an ovalbumin (OVA) model of asthma.

METHODS

Mice were subjected either to repeated, intranasal application of Af extract or to intraperitoneal immunization with OVA, followed by inhalation challenge. DL or a control fluid was given daily throughout the sensitization process. Immunoglobulin E (IgE) levels, bronchoalveolar lavage-fluid cytokines and cytology, lung histology, and physiologic responses to methacholine were assessed in the allergen-treated mice. Anti-OVA IgE responses and OVA-driven T-cell cytokine production were examined.

RESULTS

Treatment with DL did not impair IgE production but did inhibit bronchial inflammation and bronchial hyperresponsiveness in both Af- and OVA-treated mice. This inhibition required that DL be administered concurrently with allergen sensitization, indicating that the attenuation of bronchial hyperresponsiveness and inflammation was not caused by anticholinergic receptor effects. OVA-responsive T cells from DL-treated mice exhibited depressed production of IL-4, IL-5, and IL-13 and normal amounts of interferon-gamma. The amounts of IL-5 and IL-13 were also diminished in the bronchoalveolar lavage fluid.

CONCLUSION

DL, given at the time of exposure to the allergen, inhibits T(H)2 responses, the induction of allergic pulmonary inflammation, and bronchial hyperresponsiveness. These results suggest that DL or similar agents given during times of antigen exposure might alter disease progression in patients with respiratory allergy.

Desloratadine: a nonsedating antihistamine

OBJECTIVE

To review information on desloratadine, a nonsedating antihistamine.

DATA SOURCES

An English-language MEDLINE search was conducted (1966-July 2002). References of identified articles were subsequently reviewed for additional data. Schering Corporation provided unpublished information.

STUDY SELECTION/DATA EXTRACTION

Articles and abstracts pertaining to desloratadine were considered for inclusion, with emphasis on randomized, placebo-controlled, double-blind trials.

DATA SYNTHESIS

Desloratadine is approved for the treatment of symptoms associated with seasonal allergic rhinitis (SAR), perennial allergic rhinitis (PAR), and chronic idiopathic urticaria (CIU) in patients aged > or =12 years. In placebo-controlled trials, desloratadine demonstrated superior efficacy as a once-daily treatment of SAR, PAR, and CIU. Data suggest that desloratadine has antiinflammatory and decongestant activity.

CONCLUSIONS

Desloratadine appears to be a "me-too" agent, with no major differences compared with other second-generation antihistamines.

Safety and efficacy of desloratadine 5 mg in asthma patients with seasonal allergic rhinitis and nasal congestion

BACKGROUND

Antihistamines relieve most seasonal allergic rhinitis (SAR) symptoms, with the exception of nasal congestion, which is often the most troublesome symptom for patients. A nonsedating antihistamine that significantly decreases nasal congestion and improves symptoms of seasonal allergic asthma would be a significant advance in therapy.

OBJECTIVES

To evaluate the safety and efficacy of desloratadine 5 mg in patients experiencing moderate SAR, nasal congestion, and symptoms of seasonal allergic asthma.

METHODS

This 4-week, multicenter, parallel-group, double-blind study evaluated desloratadine treatment (5 mg once daily) versus placebo in 331 subjects with SAR and mild seasonal allergic asthma. Subjects evaluated SAR and asthma symptoms twice daily, recording 12-hour reflective and instantaneous severity evaluation scores. The primary efficacy parameter was the difference from baseline in AM/PM reflective total symptom scores. Changes in individual SAR and asthma symptoms were also analyzed.

RESULTS

Compared with placebo, desloratadine significantly reduced mean AM/PM reflective total symptom scores for SAR, beginning with the first dose (P < 0.001) and continuing throughout days 1 to 15 (-4.90 vs -2.98; P < 0.001) and days 1 to 29 (-5.47 vs -3.73; P < 0.001). Desloratadine significantly decreased AM/PM reflective total asthma symptom scores for days 1 to 15 (P = 0.023) and AM/PM reflective nasal congestion scores over days 1 to 15 and days 1 to 29 (P = 0.006 and P = 0.014, respectively). Desloratadine was safe and well tolerated; adverse events were similar to placebo overall.

CONCLUSIONS

Desloratadine provided significant relief from the signs and symptoms of SAR, including nasal congestion. In this patient population, symptoms of seasonal allergic asthma also improved.

Allergic rhinitis and asthma in children: disease management and outcomes

Antihistamines and inhaled glucocorticoids, which can be targeted toward multiple points in the "allergic cascade" underlying allergic rhinitis and asthma, extend the promise of enhanced outcomes in children with allergic rhinitis, asthma, or both. Antihistamine therapy confers significant relief of subjective ratings of seasonal and perennial allergic symptoms (e.g., rhinorrhea, congestion, sneezing, pruritus), whereas topical steroids alleviate such discomfort while also improving objective anatomic and functional indices of nasal patency (e.g., nasal peak inspiratory flow). Youngsters with asthma also experience substantial clinical benefits from inhaled steroids, which improve objective measures of pulmonary function and reduce rescue beta 2-agonists for symptom management and quality-of-life enhancement. This paper reviews recent clinical findings on the role of antihistamines and topical corticosteroids in pediatric allergy and asthma management, as well as the favorable effects of these medications on both objective and subjective health outcomes.

Desloratadine

Desloratadine is the orally active major metabolite of the nonsedating H1-antihistamine loratadine. The drug had no adverse cardiovascular effects in various animal models or when administered at 9 times the recommended adult dosage for 10 days in volunteers. Therapeutic dosages had no effects on wakefulness or psychomotor performance in healthy volunteers. No clinically significant interactions have been reported between desloratadine and drugs that inhibit the cytochrome P450 system, nor does the drug potentiate the adverse psychomotor effects of alcohol. Oral desloratadine 5 mg once daily for up to 4 weeks in patients with seasonal allergic rhinitis (SAR) significantly reduced nasal (including congestion) and non-nasal symptoms and improved health-related quality of life compared with placebo. Similar beneficial effects were observed in patients with SAR and coexisting asthma (in whom asthma symptoms and use of beta2-agonists were reduced). Desloratadine 5 mg once daily for 6 weeks significantly improved pruritus and reduced the number of hives compared with placebo in patients with chronic idiopathic urticaria (CIU). Sleep and daytime performance also improved. Desloratadine was well tolerated in clinical trials and had an adverse event profile similar to that of placebo in patients with SAR (with or without asthma) or CIU.

Inhibition of cytokine generation and mediator release by human basophils treated with desloratadine

BACKGROUND

Desloratadine is a non-sedating, clinically effective, anti-allergic therapy that has been shown to exhibit anti-inflammatory properties that extend beyond its ability to antagonize histamine at H(1)-receptor sites. This latter effect has been shown in vitro to be both IgE-dependent and -independent.

OBJECTIVE

In this study, we addressed the ability of desloratadine to inhibit the in vitro generation of interleukin (IL)-4 and IL-13 from human basophils while concurrently comparing its efficacy in preventing mediator release by these cells.

METHODS

Basophil-enriched suspensions were treated with various concentrations of desloratadine for 15 min before stimulating with either anti-IgE antibody, calcium ionophore, IL-3 or phorbol ester. Histamine (fluorimetry), LTC(4) (RIA) and IL-4 (ELISA) were all assayed using the same 4-h culture supernatants. IL-13 (ELISA) was measured in supernatants harvested after 20 h incubation. IL-4 mRNA expression (dilutional RT-PCR) was also examined.

RESULTS

Desloratadine was found to be nearly six-seven times more potent in preventing the secretion of IL-4 and IL-13 induced by anti-IgE than it was at inhibiting the release of histamine and LTC(4). These cytokines were equally inhibited by desloratadine following activation with ionomycin despite the lack of an effect on the histamine induced with ionomycin. Desloratadine had a lesser effect regarding inhibition of the IL-13 secreted in response to IL-3 and PMA. There was no evidence that desloratadine mediated its inhibitory effects by causing decreased cell viability. Finally, IL-4 mRNA accumulation was remarkably inhibited, by as much as 80%, following pretreatment with desloratadine.

CONCLUSION

While capable of inhibiting histamine and LTC(4) release by human basophils, desloratadine is more effective at targeting the signals regulating IL-4 and IL-13 generation in these cells. This inhibitory effect on cytokine generation provides additional evidence that this antihistamine exerts anti-inflammatory properties.

Effect of desloratadine and loratadine on rhinovirus-induced intercellular adhesion molecule 1 upregulation and promoter activation in respiratory epithelial cells

BACKGROUND

Rhinoviruses have been recently associated with the majority of asthma exacerbations for which current therapy is inadequate. Intercellular adhesion molecule 1 (ICAM-1) has a central role in airway inflammation in asthma, and it is the receptor for 90% of rhinoviruses. Rhinovirus infection of airway epithelium induces ICAM-1. Desloratadine and loratadine are compounds belonging to the new class of H(1)-receptor blockers. Anti-inflammatory properties of antihistamines have been recently documented, although the underlying molecular mechanisms are not completely defined.

OBJECTIVE

We have investigated the effects of desloratadine and loratadine on rhinovirus-induced ICAM-1 expression, mRNA upregulation, and promoter activation.

METHODS

Cultured primary bronchial or transformed (A549) respiratory epithelial cells were pretreated with desloratadine and loratadine for 16 hours and infected with rhinovirus type 16 for 8 hours. ICAM-1 surface expression was evaluated with flow cytometry, and ICAM-1 mRNA was evaluated with specific RT-PCR. In A549 cells promoter activation was evaluated with a chloramphenicol acetyltransferase assay, and binding activity of nuclear factor kappa B in nuclear extracts was evaluated with an electrophoretic mobility shift assay.

RESULTS

Desloratadine and loratadine (0.1-10 micromol/L) inhibited rhinovirus-induced ICAM-1 upregulation in both primary bronchial or transformed (A549) respiratory epithelial cells. In A549 cells the 2 compounds showed a dose-dependent inhibition with similar efficacy (inhibitory concentration of 50%, 1 micromol/L). Desloratadine and loratadine also inhibited ICAM-1 mRNA induction caused by rhinovirus infection in a dose-dependent manner, and they completely inhibited rhinovirus-induced ICAM-1 promoter activation. Desloratadine also inhibited rhinovirus-induced nuclear factor kappa B activation. Desloratadine and loratadine had no direct effect on rhinovirus infectivity and replication in cultured epithelial cells.

CONCLUSION

These effects are unlikely to be mediated by H(1)-receptor antagonism and suggest a novel mechanism of action that may be important for the therapeutic control of virus-induced asthma exacerbations.

Desloratadine activity in concurrent seasonal allergic rhinitis and asthma

Seasonal allergic rhinitis (SAR) and asthma, which are frequently comorbid, share some common allergic pathogenic bases. Clinical manifestations of these disorders might therefore be viewed as local manifestations of a systemic inflammatory state. Not only do the onsets of allergic-rhinitis (AR) and asthma symptoms often coincide (within 1 year), but also nasal challenges with SAR allergens can induce airways hyperreactivity (AHR). Eosinophils, which are key effector cells in both SAR and asthma, cause AHR, tissue damage, and neuronal effects through secretion of toxic granule proteins, enzymes, and other mediators. The novel, nonsedating, histamine H1-receptor antagonist, desloratadine, which exerts various favorable effects on the allergic cascade, significantly decreased SAR symptoms (e.g., nasal congestion) and diminished daily beta2-agonist use and improved asthma symptoms, while maintaining pulmonary function, in patients with SAR-asthma who were treated with once-daily desloratadine regimens.

Desloratadine: A new, nonsedating, oral antihistamine

Desloratadine is a new, selective, H(1)-receptor antagonist that also has anti-inflammatory activity. In vitro studies have shown that desloratadine inhibits the release or generation of multiple inflammatory mediators, including IL-4, IL-6, IL-8, IL-13, PGD(2), leukotriene C(4), tryptase, histamine, and the TNF-alpha-induced chemokine RANTES. Desloratadine also inhibits the induction of cell adhesion molecules, plateletactivating factor-induced eosinophil chemotaxis, TNF-alpha-induced eosinophil adhesion, and spontaneous and phorbol myristate acetate-induced superoxide generation in vitro. In animals desloratadine had no effect on the central nervous, cardiovascular, renal, or gastrointestinal systems. Desloratadine is rapidly absorbed, has dose-proportional pharmacokinetics, and has a half-life of 27 hours. The absorption of desloratadine is not affected by food, and the metabolism and elimination are not significantly affected by the subject's age, race, or sex. There are no clinically relevant interactions between desloratadine and erythromycin, ketoconazole, or grapefruit juice. Desloratadine is not a significant substrate of the P-glycoprotein transport system. Once daily administration of desloratadine rapidly reduces the nasal and nonnasal symptoms of seasonal allergic rhinitis, including congestion. In patients with seasonal allergic rhinitis and concomitant asthma, desloratadine treatment was also associated with significant reductions in total asthma symptom score and use of inhaled beta(2)-agonists. Use of desloratadine in patients with chronic idiopathic urticaria was associated with significant reductions in pruritus, number of hives, size of the largest hive, and interference with sleep and daily activities. Clinical experience in over 2300 patients has shown that the adverse event profile of desloratadine is similar to that of placebo; desloratadine has no clinically relevant effects on electrocardiographic parameters, does not impair wakefulness or psychomotor performance, and does not exacerbate the psychomotor impairment associated with alcohol use.

Therapeutic options in allergic disease: antihistamines as systemic antiallergic agents

As has been reported throughout this supplement, the pathophysiologic factors of allergic diseases involve many elements of systemic disease-effector-cell recruitment from circulation, stimulation of bone marrow progenitors, systemic effector-cell priming, anaphylactic reactions, and others. With this understanding, allergic inflammation can be thought of as a reflection of systemic immunologic responses with compartmentalized manifestations in various organ systems, including the upper respiratory tract, lungs, gastrointestinal tract, and skin. Thus, any therapeutic approach to the treatment of allergic disease should address, in addition to the localized disease manifestations, the systemic immunologic dysregulation. Second-generation antihistamines (cetirizine, fexofenadine, loratadine) have been used since the 1980s to treat localized allergy symptoms in upper airways, skin, and, in some cases, the lungs; however, the efficacy of these agents in controlling systemic immune dysregulation and chronic allergic inflammation (eg, nasal congestion) has not been proved. The potential role of newer antihistamines in the amelioration of both localized and systemic aspects of allergic disease represents an active area of interest. Desloratadine, a new selective histamine H(1)-receptor antagonist with potent antihistaminic and anti-inflammatory activity, is introduced and its potential for treating the systemic aspects of allergic disease is discussed.