Desloratadine citrate disodium injection, a potent histamine H(1) receptor antagonist, inhibits chemokine production in ovalbumin-induced allergic rhinitis guinea pig model and histamine-induced human nasal epithelial cells via inhibiting the ERK1/2 and NF-kappa B signal cascades

Chemokines have chemotactic properties on leukocyte subsets whose modulation plays a pivotal role in allergic inflammatory processes. Our present study was designed to investigate the anti-allergic and anti-inflammatory properties of desloratadine citrate disodium injection (DLC) and elucidate the molecular mechanisms of its anti-inflammatory properties. The anti-allergic effects of DLC were evaluated based on allergic symptoms, serological marker production and histological changes of the nasal mucosa in guinea pigs model of allergic rhinitis. The anti-inflammatory properties and molecular mechanisms of DLC were explored by studying the regulation of a set of chemokines and extracellular signal-regulated kinase (ERK)1/2 and nuclear factor-kappa B (NF-κB) pathways, after DLC treatment in guinea pigs model of allergic rhinitis in vivo and histamine-activated human nasal epithelial cells (HNECs) in vitro. In vivo model in guinea pigs, DLC alleviated the rhinitis symptoms, inhibited inflammatory cells infiltration in nasal lavage fluid (NLF) and histamine, monocyte chemotactic protein (MCP)-1, regulated on activation normal T cell expressed, and presumably secreted (RANTEs) and interleukin (IL)-8 release in sera and P-ERK1/2 and NF-κB activation in nasal mucosa. In vitro, DLC markedly inhibited histamine-induced production of MCP-1, RANTEs and IL-8 and suppressed c-Raf, mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK) and ERK1/2 activation in HNECs. These results provide evidence that DLC possesses potent anti-allergic and anti-inflammatory properties. The mechanism of action underlying DLC in allergic inflammation appears to be inhibition of the phosphorylation of ERK1/2, in addition to blocking of the NF-κB pathway.

Desloratadine for the Relief of Nasal and Non-nasal Allergy Symptoms: An Observational Study

Introduction

The rates of allergic rhinitis, allergic asthma, and atopic eczema range from 6% to 16% globally. Second-generation antihistamines have been shown to be safe and effective for the treatment of symptoms of allergic disease. This study investigated the efficacy and safety of desloratadine, a nonsedating second-generation antihistamine, in the treatment of common allergy symptoms.

Methods

In this open-label, uncontrolled, non-randomized, observational study, subjects (N = 973) with allergy symptoms were given desloratadine 5 mg daily for 3 weeks. Nasal, ocular, and dermal symptom severity was rated as asymptomatic, mild, moderate, or severe; changes in the percentage of subjects in each severity category were assessed. Overall efficacy and tolerability of desloratadine treatment were evaluated separately by physicians and subjects.

Results

Allergic rhinitis was the most frequent diagnosis, occurring in 59.0% of subjects. Approximately 40% of subjects had received previous treatment with other antihistamines, systemic/topical glucocorticosteroids, or beta-sympathicomimetics. Slightly more than half of subjects received concomitant medication during the study; 263 (53.0%) of those used intranasal steroids. A significant reduction in severity scores was observed in all symptom subgroups (P < 0.001). Desloratadine efficacy was judged to be excellent or good by 90.2% of physicians and 88.6% of subjects; 82.5% of investigators and 80.9% of subjects considered it more effective than previous therapy. The tolerability of desloratadine was rated excellent or good by 97.0% of both groups. Thirty-one subjects (3.2%) experienced adverse events.

Conclusions

In an open-label, uncontrolled, non-randomized, observational study allergy symptoms improved significantly in subjects treated with desloratadine.

Anti-inflammatory properties of desloratadine

BACKGROUND

Allergic rhinitis (AR) is associated with robust infiltration of immune cells and mediators that may contribute to clinical manifestations of the disease.

OBJECTIVE

To review the complex immune effector mechanisms involved in the allergic response and discuss their effects on the pathophysiological and clinical manifestations of AR. Desloratadine, a novel antihistamine, was used as a probe with the goal of attaining a better understanding of the inflammatory processes underlying the allergic response.

METHODS

Data were obtained from abstracts and peer-reviewed journals. The pathophysiology of the allergic response has been extensively studied. This paper presents only data from studies that used desloratadine at physiologically relevant concentrations.

RESULTS

Key mediators involved in the allergic response and in pathophysiological and clinical manifestations of the immune response were reviewed. Desloratadine was used as a probe to further elucidate the mechanisms involved during an allergic response.

CONCLUSIONS

Some have proposed a link between the pathophysiology of AR and the clinical manifestation of symptoms. Desloratadine, a new-generation antihistamine, has demonstrated anti-inflammatory effects in vitro; indeed, desloratadine is capable of intervening at various points in the immune cascade. Although in vitro results do not necessarily correlate with clinical efficacy, the anti-inflammatory properties of desloratadine may contribute to its efficacy in patients with AR, allergy-induced asthma, and other related allergic conditions. Antihistamines that modulate in the immune system at various stages may optimize treatment of allergic disease.

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.

Desloratadine Inhibits Constitutive and Histamine-Stimulated Nuclear Factor-κB Activity Consistent with Inverse Agonism at the Histamine H1 Receptor

BACKGROUND

The human histamine H1 receptor is constitutively active and exhibits basal activation of nuclear factor-kappaB (NF-kappaB), an important modulator of allergic inflammation. Certain H1 antihistamines have recently been shown to inhibit basal NF-kappaB activity by stabilizing the H1 receptor in an inactive state, a phenomenon called 'inverse agonism'.

METHODS

We evaluated the effect of the new H1 antihistamine, desloratadine, on basal and histamine-stimulated NF-kappaB activity and compared it with the activities of other H1 antihistamines.

RESULTS

Transiently transfected COS-7 cells co-expressing NF-kappaB-luciferase and the H1 receptor exhibited constitutive NF-kappaB activity. H1 antihistamines reduced basal NF-kappaB activity (rank order of potency: desloratadine > pyrilamine > cetirizine > loratadine > fexofenadine). Histamine stimulated basal NF-kappaB activity 8-fold, which was blocked by H1 antihistamines (rank order of potency: desloratadine > cetirizine > pyrilamine > loratadine > fexofenadine). Neither histamine nor antihistamines had any effect on NF-kappaB activity in the absence of the H1 receptor.

CONCLUSIONS

Desloratadine, acting through the histamine H1 receptor, inhibited basal NF-kappaB activity and can thus be classified as an inverse agonist. Inhibition of basal and histamine-stimulated NF-kappaB activity may help to explain previously reported inhibitory effects of desloratadine on allergic inflammatory mediators.

Recent advances in the treatment of rhinitis and rhinosinusitis

Current rhinitis treatment is unsatisfactory for many patients, possibly because monotherapy is employed, without regard to the major presenting symptom. Recognition of the impact of rhinitis on quality of life and on associated disorders such as asthma has led to the development of guidelines, use of which has been shown to improve symptom control and quality of life compared to unguided therapy. The role of antihistamines, topical corticosteroids and anti-leukotrienes is discussed.