The clinical relevance of the anti-inflammatory properties of antihistamines

Anti-allergic and anti-inflammatory properties of a potent histamine H1 receptor antagonist, desloratadine citrate disodium injection, and its anti-inflammatory mechanism on EA.hy926 endothelial cells

The present study, demonstrates that, desloratadine citrate disodium injection (DLC) possesses antihistaminic, anti-allergic and anti-inflammatory properties and elucidates its molecular mechanisms of anti-inflammatory properties. In vitro antihistamine activity of DLC was determined in guinea pig isolated tissues. In vivo antihistamine effects were evaluated after following intravenous administration of DLC in mice with histamine- induced paw edema and in rats with increased capillary permeability. Anti-allergic effects were assessed through passive cutaneous anaphylactic (PCA) reactions in sensitized rodents and ovalbumin-induced allergic rhinitis in rats. Anti-inflammatory properties and molecular mechanisms of DLC were determined on histamine- and lipopolysaccharide (LPS)-induced EA.hy926 endothelial cells. DLC exhibited significant and reversible inhibition of histamine-induced contractions of isolated guinea pig ileum with pA2 value of 8.88. Histamine-induced paw edema and increased capillary permeability were notably inhibited by DLC intravenous administration. In the model of PCA reactions, DLC showed significant activity in a dose-dependent nd potently inhibited both the early-phase and late-phase allergic reaction of ovalbumin-induced allergic rhinitis in rats. DLC alleviated the rhinitis symptoms and inhibited inflammatory cell infiltration, IL-4 and protein leakage in nasal lavage fluid (NLF). In EA.hy926 cells, DLC significantly inhibited the histamine- and LPS- induced IL-6 and IL-8 production and P-selectin and intercellular cell adhesion molecule-1 (ICAM-1) expression. Moreover, DLC reduced translocation of nuclear factor-kappaB (NF-κB) to the nucleus in activated EA.hy926 cells. These results provide evidence that DLC possesses potent antihistaminic, anti-allergic and, anti-inflammatory properties via suppressing IL-6, IL-8, P-selectin and ICAM-1 expression.

Efficacy and safety of rupatadine for allergic rhino-conjunctivitis: a systematic review of randomized, double-blind, placebo-controlled studies with meta-analysis

BACKGROUND

Allergic rhinitis is a complex inflammatory disease whose pathophysiology involves local and systemic mechanisms. Rupatadine, a molecule with intense antihistaminic activity and with antagonist PAF effects through its interaction with specific receptors, is indicated for the treatment of intermittent or persistent allergic rhinitis and urticaria.

SCOPE

This systematic review was aimed at identifying in the most important databases, up to January 2013, the double-blind placebo-controlled randomized trials administering rupatadine in allergic rhinitis. No restriction was introduced for treatment duration and dose, study design, population age, allergen exposition and disease classification. The methodological quality of included studies and risk of bias were systematically assessed. Meta-analysis was performed when possible to summarize information.

FINDINGS

Seventeen of 413 initially identified records were fully assessed for eligibility. Ten trials involving 2573 patients overall met the inclusion criteria and entered the analysis. Their internal validity was satisfactory. Data synthesis showed that rupatadine is superior to placebo in relieving the overall allergy symptoms on reflective (SMD: -0.37, 95% CI -0.46 to -0.27; p < 0.00001) and instantaneous (SMD: -0.41, 95% CI -0.71 to -0.11; p = 0.007) assessment, the nasal symptoms considered together (reflective SMD: -0.36, 95% CI -0.48 to -0.25; p < 0.00001; instantaneous SMD: -0.39, 95% CI -0.61 to -0.17; p = 0.0004) or individually and ocular symptoms. Inter-study heterogeneity was low for the main outcomes and the risk of publication bias was judged as unlikely. A number of secondary endpoints were favorably affected by rupatadine. No difference was observed in the incidence of total adverse reactions between rupatadine and placebo (OR 1.23, 95% CI 0.95 to 1.59; p = 0.12).

CONCLUSION

Randomized double-blind controlled trials show a favorable risk-benefit ratio in rupatadine for the treatment of allergic rhino-conjunctivitis. This evidence is strengthened when data are pooled in the form of meta-analysis, where accurate and robust effect estimations are derived from a large population.

Design, synthesis and pharmacological screening of a series of N1-(substituted)aryl-5,7-dimethyl-2-(substituted)pyrido(2,3-d)pyrimidin-4(3H)-ones as potential histamine H1-receptor antagonists

A series of N1-(substituted)aryl-5,7-dimethyl-2-(substituted)pyrido(2,3-d)pyrimidin-4(3H)-one was designed on the basis of the triangular pharmacophoric requirement of histamine H1-receptor antagonists. The designed series was synthesized by cyclo-condensation of monoaryl thiourea with ethyl cyanoacetate in the presence of dry HCl gas to give N1-(substituted aryl)-2-mercaptopyrimidine-4(3H)-one, which on cyclo-condensation with acetylacetone gave the pyridopyrimidinone. Further methylation of the mercapto group at C-2 with methyl iodide followed by nucleophilic displacement of the methylmercapto group by various amines gave the targeted compounds. All the synthesized compounds were screened for histamine H1-receptor antagonistic activity by the in vitro method of inhibition of the isotonic contraction induced by histamine on isolated guinea pig ileum using cetirizine as a standard drug. All the compounds exhibited potent histamine H1-receptor antagonistic activity with pA2 values from 7.30- 9.75 (cetirizine, pA2 value 9.40). The potent compounds were screened for their in vivo antihistaminic activity by protection of animal from asphyxic shock. The sedative potential of potent compounds was checked on albino mice by photoactometer and they had comparative sedative potential to the standard drug cetirizine. None of the compound exhibited anticholinergic activity in the in vitro rat ileum model.

Antihistamines and their role as antipruritics

Antihistamines that bind to the histamine 1 receptor (H1) serve as important therapeutic agents to counter the effects of histamine in the skin. Two generations of antihistamines exist; however, second-generation agents are more advantageous because they cause less sedation, have a longer half life and are more selective for the H1 receptor. While H1 antihistamines have proven to be effective at reversing the pruritus and cutaneous lesions of chronic urticaria, their ability to treat pruritus associated with other cutaneous and systemic diseases is unproven.

Potential of levocetirizine in the relief of nasal congestion

Nasal congestion is a common and troublesome symptom of allergic rhinitis. Because it impairs the natural human drive for nasal breathing, it -- in addition -- leads to lower self-esteem and to impaired quality of life. It is a symptom that is difficult to treat. Traditionally, intranasal steroids, because of their potent anti-inflammatory properties, and vasoconstrictors have been utilized for relieving the nasal passages from the inflamed and congested mucosal tissues. Recent studies with the last-generation antihistamines have demonstrated the decongestant properties of these antihistamines in both the more acute seasonal allergic rhinitis and the more chronic and lasting perennial allergic rhinitis. This study aims to review the efficacy of the potent antihistamine, levocetirizine, in relieving nasal congestion as reported in various studies and settings. Comparisons with placebo and with other antihistamines have been presented in order to help general medical practitioners differentiate between the properties of the various available antihistamines.

Cetirizine: a review of its use in allergic disorders

Cetirizine is a selective, second-generation histamine H1 receptor antagonist, with a rapid onset, a long duration of activity and low potential for interaction with drugs metabolised by the hepatic cytochrome P450 system. Cetirizine was generally more effective than other H1 receptor antagonists at inhibiting histamine-induced wheal and flare responses. Cetirizine is an effective and well tolerated agent for the treatment of symptoms of seasonal allergic rhinitis (SAR), perennial allergic rhinitis (PAR) and chronic idiopathic urticaria (CIU) in adult, adolescent and paediatric patients. In adults with these allergic disorders, cetirizine was as effective as conventional dosages of ebastine (SAR, PAR, CIU), fexofenadine (SAR), loratadine (SAR, CIU) or mizolastine (SAR). This agent was significantly more effective, and with a more rapid onset of action, than loratadine in 2-day studies in environmental exposure units (SAR). In paediatric patients, cetirizine was as at least as effective as chlorphenamine (chlorpheniramine) [SAR], loratadine (SAR, PAR) and oxatomide (CIU) in the short term, and more effective than oxatomide and ketotifen (PAR) in the long term. Cetirizine was effective in reducing symptoms of allergic asthma in adults and reduced the relative risk of developing asthma in infants with atopic dermatitis sensitised to grass pollen or house dust mite allergens. It had a corticosteroid-sparing effect in infants with severe atopic dermatitis and was effective in ameliorating reactions to mosquito bites in adults. Cetirizine was well tolerated in adults, adolescents and paediatric patients with allergic disorders. In adult, adolescent and paediatric patients aged 2-11 years, the incidence of somnolence with cetirizine was dose related and was generally similar to that with other second-generation H1 receptor antagonists. Although, its sedative effect was greater than that of fexofenadine in some clinical trials and that of loratadine or fexofenadine in a postmarketing surveillance study. In infants aged 6-24 months, the tolerability profile of cetirizine was similar to that of placebo. Cetirizine did not have any adverse effects on cognitive function in adults, or cognitive function, behaviour or achievement of psychomotor milestones in paediatric patients. Cetirizine was not associated with cardiotoxicity.

CONCLUSION

Cetirizine is well established in the treatment of symptoms of SAR, PAR or CIU. It demonstrated a corticosteroid-sparing effect and reduced the relative risk of developing asthma in sensitised infants with atopic dermatitis. Cetirizine was effective in the treatment of allergic cough and mosquito bites; however, its precise role in these indications has yet to be clearly established. On the basis of its favourable efficacy and tolerability profile and rapid onset of action, cetirizine provides an important option for the treatment of a wide range of allergic disorders.

Synthesis and Structure−Activity Relationships of Novel Histamine H1 Antagonists: Indolylpiperidinyl Benzoic Acid Derivatives

A series of indolylpiperidinyl derivatives were prepared and evaluated for their activity as histamine H(1) antagonists. Structure-activity relationship studies were directed toward improving in vivo activity and pharmacokinetic profile of our first lead (1). Substitution of fluorine in position 6 on the indolyl ring led to higher in vivo activity in the inhibition of histamine-induced cutaneous vascular permeability assay but lower selectivity toward 5HT(2) receptor. Extensive optimization was carried out within this series and a number of histamine H(1) antagonists showing potency and long duration of action in vivo and low brain penetration or cardiotoxic potential were identified. Within this novel series, indolylpiperidines 15, 20, 48,51 and 52 exhibited a long half-life in rat and have been selected for further preclinical evaluation.

Levocetirizine better protects than desloratadine in a nasal provocation with allergen

BACKGROUND

Direct comparisons of antihistamines are rare but very much needed. Newly available antihistamine preparations, levocetirizine, the R-enantiomer of racemate cetirizine, and desloratadine, an active metabolite of loratadine, have been recently released for allergic rhinitis.

OBJECTIVE

We sought to compare levocetirizine and desloratadine in a nasal provocation test (NPT) with grass pollen.

METHODS

Twenty-four volunteers with grass pollen allergy and a history of rhinitis were enrolled in a double-blind, placebo-controlled, crossover study. Three NPTs were performed in a dose-escalating manner during the out-of-season period 4 hours after a single dose of levocetirizine (5 mg), desloratadine (5 mg), or placebo.

RESULTS

CONCLUSIONS

This study demonstrates a better overall protection of a single dose of levocetirizine compared with desloratadine in an NPT with grass pollen allergen. In contrast to late-phase inflammatory markers, which were unaffected, extravascular leakage of the early-phase marker albumin was significantly limited by levocetirizine.

Role of allergy in rhinosinusitis

PURPOSE OF REVIEW

Allergic rhinitis and rhinosinusitis are common diseases occurring in both children and adults that consume enormous amounts of health care dollars. In addition to its own costs, allergic rhinitis is considered a major predisposing factor for the development of rhinosinusitis. Whereas many authors suggest a clinical association between these two diseases, the mechanism of how allergic rhinitis predisposes to rhinosinusitis or affects the course of rhinosinusitis remains unclear.

RECENT FINDINGS

Limited progress has been made in understanding the pathophysiologic mechanism involved in the interaction. Progress in immunologic technique emphasizes the importance of inflammatory cells, especially eosinophils, mast cells, and T lymphocytes, and their mediators. Some authors have proposed a role for neurogenic pathways, whereas others have focused on systemic involvement. Little progress has been made in intervention studies that support the importance of allergic rhinitis in altering the course of acute or chronic rhinosinusitis.

SUMMARY

This paper reviews the limited new literature available to update knowledge that supports the association of allergic rhinitis with rhinosinusitis, mechanisms potentially underlying the association, and implications of this knowledge for therapy.

Cc-chemokine eotaxin as a marker of efficacy of specific immunotherapy in patients with intermittent IgE-mediated allergic rhinoconjunctivitis

BACKGROUND

Allergen-specific immunotherapy (SIT) is believed to be a valuable remedy in several allergic diseases; however, an accurate immunological marker of the efficacy of this treatment method has not been found yet. Cc-chemokine eotaxin, owing to its selective action on eosinophils, seems to play an important role in the pathophysiology of allergic response. The purpose of this study was to assess the usefulness of eotaxin in monitoring of SIT efficacy in patients with IgE-mediated allergic rhinoconjunctivitis.

METHODS

One hundred and twenty-two patients with seasonal IgE-mediated allergic rhinoconjunctivitis due to tree- (birch, n = 42; hazel/alder, n = 14) or grass/cereal- (n = 66) pollen received allergen-specific immunotherapy. Serum eotaxin levels were determined four times in every patient, shortly before immunotherapy (Evaluation 0), immediately after the treatment (Evaluation 1), in the height of pollen season (Evaluation 2) and at least 2 weeks after the pollen season (Evaluation 3). Serum eotaxin levels were simultaneously measured in 59 healthy people from the control group. Changes in serum eotaxin levels were assessed in the healthy and allergic groups. Clinical symptoms of IgE-mediated rhinoconjunctivitis were evaluated and compared with serum eotaxin concentration changes.

RESULTS

Mean values of eotaxin concentrations in serum during Evaluations 0-3 did not significantly differ in the healthy subjects and the patients with IgE-mediated rhinoconjunctivitis (P > 0.05). Moreover, no statistically significant differences in the serum eotaxin levels between the visits were observed in the patients who received immunotherapy (P > 0.05); however, immediately after immunotherapy (Evaluation 1) the mean serum level of eotaxin was lowest and closest to the serum eotaxin concentration in the control group at the same visit. No significant correlation between the mean value of the serum eotaxin level in the height of pollen season (r = -0.12, P > 0.05) or mean changes of the eotaxin levels between Evaluations 2 and 1 (r = -0.03, P > 0.05), on the one hand, and the cumulative score of symptoms and drug, on the other, were found.

CONCLUSIONS

The results allow to conclude that although eotaxin plays a significant role in the mechanism of antigen-specific immunotherapy, its serum expression remains a poor marker of SIT efficacy.

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.

Cetirizine and levocetirizine inhibit eotaxin-induced eosinophil transendothelial migration through human dermal or lung microvascular endothelial cells

BACKGROUND

Several second-generation antihistamines have documented anti-inflammatory effects which appear independent of H1-receptor blockade. We investigated the inhibitory effect of cetirizine and its active enantiomer levocetirizine on eosinophil transendothelial migration (TEM) through monolayers of normal human dermal microvascular endothelial cells (HMVEC-d) or human lung microvascular endothelial cells (HMVEC-l).

METHODS

HMVEC-d or HMVEC-l were grown to confluence on micropore filters in transwells inserted into a 24-well tissue culture dish. Eosinophils were isolated by density gradient centrifugation and negative immunomagnetic selection. Untreated eosinophils or eosinophils pre-incubated (30 min at 37 degrees C) with a concentration range of cetirizine or levocetirizine (10-5 to 10-9 m) were added to the upper chamber of the transwell which was incubated for 60 min at 37 degrees C. Both spontaneous eosinophil TEM and TEM to 100 ng/mL of human eotaxin in the lower chamber were assessed.

RESULTS

Between 8 and 10% of the eosinophils added to the upper chamber underwent spontaneous TEM through HMVEC-d or HMVEC-l. The addition of eotaxin to the lower chamber enhanced eosinophil TEM through HMVEC-d or HMVEC-l monolayers to over 20%, i.e. an enhanced TEM of approximately 100% in each case. Pre-incubation of eosinophils with cetirizine or levocetirizine dose-dependently inhibited eosinophil TEM to eotaxin through both HMVEC-d or HMVEC-l with total inhibition of eotaxin-induced TEM observed at 10-8 m for HMVEC-d and 10-7 m for HMVEC-l. Both drugs gave a reduced but significant inhibition of eosinophil TEM at lower concentrations. No concentration of cetirizine or levocetirizine had any significant effect on expression of CD11b, CD18 or CD49d by either resting or eotaxin-stimulated eosinophils. Furthermore, no effect on spontaneous eosinophil TEM, or eosinophil viability was seen with any concentration of cetirizine or levocetirizine.

CONCLUSION

Levocetirizine inhibits eotaxin-induced eosinophil TEM through both dermal and lung microvascular endothelial cells suggesting that, like cetirizine, levocetirizine has potential anti-inflammatory effects.

Comparison of five new antihistamines (H1-receptor antagonists) in patients with allergic rhinitis using nasal provocation studies and skin tests

BACKGROUND

It was the aim of the authors to compare all of the latest second-generation antihistamines and to see if there were significant differences in their efficacy. It is important for ENT specialists to know if these differences exist, as it is for general practitioners trying to choose between these drugs.

METHODS

In 12 confirmed grass pollen allergic patients the authors performed nasal smears to asses eosinophilia, histamine/grass pollen skin tests, and grass pollen nasal provocation tests. All tests were performed before and after administration of one of five different antihistamines (cetirizine, loratadine, ebastine, fexofenadine, mizolastine) or placebo. The order of administration of antihistamines and placebo was randomised, and patients were not aware of which drug they were given. A decrease in nasal eosinophilia (nasal smear), or nasal or skin reactivity (provocation tests) was looked for.

RESULTS

A significant decrease in nasal eosinophilia was observed for all antihistamines but not for placebo. For the grass pollen nasal provocation tests, the decrease was significant for nasal blockage and sneezing; for rhinorrhea there was an insignificant decrease that was true for all antihistamines. A significant reduction in histamine/grass pollen skin test reactivity was also observed for all antihistamines, during an 8 h observation period. A significant difference in efficacy between the different antihistamines could not be found with any of the tests performed.

CONCLUSIONS

For the newer nonsedating H1-antagonists there appears to be no clinically relevant differences in activities--at least not in our study. Preference of the patient may be the most important factor in making a choice between these drugs.