Treatment of urticaria. An evidence-based evaluation of antihistamines

Existing bitter medicines for fighting 2019-nCoV-associated infectious diseases

The sudden outbreak of COVID-19 has led to more than seven thousand deaths. Unfortunately, there are no specific drugs available to cure this disease. Type 2 taste receptors (TAS2Rs) may play an important role in host defense mechanisms. Based on the idea of host-directed therapy (HDT), we performed a negative co-expression analysis using big data of 60 000 Affymetrix expression arrays and 5000 TCGA data sets to determine the functions of TAS2R10, which can be activated by numerous bitter substances. Excitingly, we found that the main functions of TAS2R10 involved controlling infectious diseases caused by bacteria, viruses, and parasites, suggesting that TAS2R10 is a key trigger of host defense pathways. To quickly guide the clinical treatment of 2019-nCoV, we searched currently available drugs that are agonists of TAS2Rs. We identified many cheap, available, and safe medicines, such as diphenidol, quinine, chloroquine, artemisinin, chlorpheniramine, yohimbine, and dextromethorphan, which may target the most common symptoms caused by 2019-nCoV. We suggest that a cocktail-like recipe of existing bitter drugs may help doctors to fight this catastrophic disease and that the general public may drink or eat bitter substances, such as coffee, tea, or bitter vegetables, to reduce the risk of infection.

The therapeutic versatility of antihistamines: A comprehensive review

Antihistamines are common and readily available medications for primary care patients and those seeking over-the-counter treatments. This article provides an overview of available antihistamines, their mechanisms of action, safety concerns in specific populations, and their therapeutic uses in several common conditions.

Nitrogen Bridged Diazocines: Photochromes Switching within the Near-Infrared Region with High Quantum Yields in Organic Solvents and in Water

Diazocines are bridged azobenzenes with superior photophysical properties. In contrast to azobenzenes the Z configuration is thermodynamically stable and the E isomer is metastable. We present a new class of nitrogen bridged diazocines with bathochromically shifted switching wavelengths and remarkably high quantum yields (-NH-CH₂- bridged diazocine: Φ_Z→E = 0.57, Φ_E→Z = 0.8). Z to E isomerization is induced by irradiation with blue light, whereas switching back to the Z isomer is accomplished with light in the near-infrared window (up to 740 nm), which is important for medical applications like photopharmacology (deep tissue penetration). Furthermore, substitution at the bridging nitrogen should provide access to widely applicable tricyclic, photoswitchable pharmacophores. The -NAc-CH₂- bridged derivative is soluble in water, and all photophysical properties (conversion rates, quantum yields, and thermal half-lives) are largely retained. Hence, this diazocine is an ideal photoswitch for applications in biochemical systems and in photopharmacology.

Allergic Dermatoses

The purpose of this article is to review the current available material pertaining to atopic dermatitis, contact dermatitis, urticaria, and angioedema. This article focuses on each disease process's clinical presentation, diagnosis, and management. Although atopic dermatitis and contact dermatitis are similar, their development is different and can affect a patient's quality of life. Urticaria and angioedema are also similar, but the differentiation of the two processes is crucial in that they have significant morbidity and mortality, each with a different prognosis.

Update on the treatment of chronic urticaria

Chronic spontaneous urticaria, also known as chronic idiopathic urticaria or simply chronic urticaria, is a common disorder that has a prevalence in the general population that ranges between 0.5% and 1%. This condition negatively affects the patient's quality of life and has considerable impact on direct and indirect health-related costs. Chronic urticaria is difficult to manage. Nonsedating H1 antihistamines are the first line of therapy, but fewer than 50% of patients experience relief at recommended dosages. Although guidelines call for increasing the dosage when response is inadequate, some patients still do not achieve adequate control of symptoms. New treatment alternatives, with proven efficacy under the standards of evidence-based medical practice, must therefore be developed.

Allergic manifestations and cutaneous histamine responses in patients with McCune Albright syndrome

Background

McCune Albright syndrome (MAS) is a rare disorder characterized by precocious puberty, café-au-lait spots, and fibrous dysplasia. Its cause is an activating mutation in the GNAS gene, encoding a subunit of the stimulatory G protein, G_salpha (G_sα). The action of any mediator that signals via G_sα and cyclic AMP can be up regulated in MAS. We had observed gastritis, gastroesophageal reflux, and anaphylaxis in McCune Albright patients.

Objective

As histamine is known to signal via histamine 1 (H1) and histamine 2 (H2) receptors, which couple with stimulatory G proteins, we attempted to mechanistically link histamine responsiveness to the activating GNAS mutation. We hypothesized that responsiveness to histamine skin testing would differ between MAS patients and healthy controls.

Patients and methods

After obtaining informed consent, we performed a systematic review of histamine responsiveness and allergic manifestations in 11 MAS patients and 11 sex-matched, Tanner-stage matched controls. We performed skin prick testing, quantifying the orthogonal diameters of wheals and erythema. We also quantitated G protein mRNA expression.

Results

The peak wheal and flare responses to histamine were significantly higher in MAS patients compared to controls.

Conclusions

This study suggests that MAS patients may be at risk for exaggerated histamine responsiveness compared to unaffected controls.

Dose dependency of brain histamine H(1) receptor occupancy following oral administration of cetirizine hydrochloride measured using PET with [11C]doxepin

AIMS

The strength of sedation due to antihistamines can be evaluated using positron emission tomography (PET). The purpose of the present study is to measure histamine H(1) receptor (H(1)R) occupancy following oral administration of cetirizine (10 and 20 mg) in order to examine dose dependency.

METHODS

Fifteen healthy male volunteers (age range, 20-35 years) were divided into 3 subgroups and were studied following single oral administration of cetirizine at 10 mg (n = 5) and 20 mg (n = 5) or hydroxyzine at 30 mg (n = 5) using PET with 11C-doxepin. Each subject was scanned also following the administration of placebo. Binding potential and H(1)RO values were calculated in the prefrontal and anterior cingulate cortices. Subjective sleepiness was also measured, and the correlation to H(1)RO was examined for each antihistamine.

RESULTS

The averaged H(1)ROs of cetirizine 10 mg, 20 mg, and hydroxyzine 30 mg in the prefrontal and cingulate cortices was 12.6%, 25.2%, and 67.6%, respectively. The H(1)RO of hydroxyzine 30 mg correlated well with subjective sleepiness (p < 0.001); however, those of cetirizine 10 and 20 mg showed no correlation with subjective sleepiness.

CONCLUSION

It was demonstrated that the brain penetration of orally administered cetirizine was dose-dependent. Cetirizine 10 mg, with its low H(1)RO and thus minimal sedation, could be more safely used than cetirizine 20 mg for the treatment of various allergic disorders.

Contact urticaria: present scenario

Immunological contact urticaria is a hypersensitivity reaction that appears on the skin following contact with an eliciting substance. Recent advances in our understanding of the molecular mechanism and pathogenesis of this reaction have altered its classification, diagnosis, and treatment. We discuss classification, epidemiology, diagnosis, testing, and treatment options that are available to patients with contact urticaria.

Impact of Desloratadine on Symptoms and Quality of Life in Subjects with Chronic Idiopathic Urticaria: A Multicenter, Practice-based Study

Background

Controlled trials have demonstrated the efficacy of antihistamines in the treatment of chronic idiopathic urticaria. Second-generation antihistamines are recommended as first-line therapy for chronic idiopathic urticaria. The purpose of this study was to determine the effect of desloratadine, a newer, nonsedating, second-generation antihistamine, on symptoms of chronic idiopathic urticaria, disease severity, and quality of life (QoL).

Methods

In an open-label, observational, multicenter study, 348 subjects with chronic idiopathic urticaria were given 5 mg of desloratadine once daily for 2 weeks. Outcome measures included change from baseline at Day 14 using the Aerius Quality of Life Questionnaire (AEQLQ); change from baseline in pruritus score, number and maximum size of hives, sleep quality, and activity impairment; and subjects' response to therapy.

Results

Desloratadine significantly decreased subjects' overall condition and symptom scores from baseline to Day 14 (2.19 ± [SD] 0.66 and 1.14 ± 0.89, respectively; P < 0.0001). Desloratadine treatment significantly improved all 10 AEQLQ domain scores from baseline to Day 7 and Day 14 (P < 0.0001). Sleep disturbance scores decreased 40% from baseline to Day 7 (1.42 ± 1.03 to 0.85 ± 0.89, respectively), and interference with daily outdoor activity scores showed a 41% decrease from baseline to Day 7 (1.11 ± 0.98 to 0.66 ± 0.90) (P < 0.0001 for both). There were significant reductions in itching, size of hives, and hive score at both Days 7 and 14. Treatment resulted in moderate, marked, or complete relief of symptoms in 76.2% of subjects. Desloratadine was well tolerated, with no adverse events reported.

Conclusion

In an open-label, observational study, desloratadine 5 mg once daily significantly decreased symptoms of chronic idiopathic urticaria and improved subject QoL.

A survey of emergency department management of acute urticaria in children

OBJECTIVES

To describe emergency department management of acute urticaria in children and to determine factors associated with management strategies and adherence to practice guidelines.

METHODS

Self-administered cross-sectional survey mailed to all Section of Emergency Medicine members of the American Academy of Pediatrics (n = 1190) and 1000 randomly selected members of the American College of Emergency Physicians. Main outcome measure was proportion of respondents adhering to published guidelines. Factors associated with management strategies were analyzed using bivariate and logistic regression analyses.

RESULTS

Of 2190 surveys sent, 1137 (52.5%) were available for analysis. Respondents included 44.6% pediatric emergency physicians, 36.4% emergency physicians, and 15.3% pediatricians. First-generation histamine (H)1 antagonists alone were the most common therapy used on initial presentation of acute urticaria, followed by corticosteroids, H2 antagonists, and second-generation H1 antagonists, used by only 7.8%, despite their recommendation as first-line therapy. Physicians working in an emergency department as opposed to an urgent or primary care setting were less likely to use second-generation H1 antagonists (odds ratio [OR], 0.3 [0.1-0.7]). General emergency physicians were 2.6 times more likely to use H2 antagonists and more than 3 times as likely to use corticosteroids. Only 14.2% of physicians overall were familiar with guideline recommendations.

CONCLUSIONS

Minimal awareness and use of existing guidelines, and low concordance with published recommendations exist. Management practices vary and are influenced by training, practice setting, and clinical experience.

The physiological and pathophysiological roles of neuronal histamine: an insight from human positron emission tomography studies

Histamine neurons are exclusively located in the posterior hypothalamus, and project their fibers to almost all regions of the human brain. Although a significant amount of research has been done to clarify the functions of the histaminergic neuron system in animals, a few studies have been reported on the roles of this system in the human brain. In past studies, we have been able to clarify some of the functions of histamine neurons using different methods, such as histamine-related gene knockout mice or human positron emission tomography (PET). The histaminergic neuron system is known to modulate wakefulness, the sleep-wake cycle, appetite control, learning, memory and emotion. Accordingly we have proposed that histamine neurons have a dual effect on the CNS, with both stimulatory and suppressive actions. As a stimulator, neuronal histamine is one of the most important systems that stimulate and maintain wakefulness. Brain histamine also functions as a suppressor in bioprotection against various noxious and unfavorable stimuli of convulsion, drug sensitization, denervation supersensitivity, ischemic lesions and stress susceptibility. This review summarizes our works on the functions of histamine neurons using human PET studies, including the development of radiolabeled tracers for histamine H1 receptors (H1R: (11)C-doxepin and (11)C-pyrilamine), PET measurements of H1R in depression, schizophrenia, and Alzheimer's disease (AD), and studies on the sedative effects of antihistamines using H(2)(15)O and H1R occupancy in the human brain. These molecular and functional PET studies in humans are useful for drug development in this millennium.

Desloratadine 5 mg once daily improves the quality of life of patients with chronic idiopathic urticaria

BACKGROUND

Chronic urticaria is known to debilitate a person's quality of life via sleep disruption, itching lesions, fatigue, social isolation, energy loss and emotional/sexual difficulties. Once-daily desloratadine significantly improved the signs and symptoms of CIU.

OBJECTIVE

Assess the effect of desloratadine 5 mg once daily on the quality of life of patients suffering of chronic idiopathic urticaria (CIU). Study population One-hundred twenty-one consecutive patients with CIU present for at least 6 weeks prior to inclusion and with a current flare of at least 3 weeks, were included in the study in 24 Belgian centres.

RESULTS

The mean dermatology life quality index (DLQI) significantly decreased from baseline to day 7 and further to day 42. Sixty per cent and 77% of patients had a clinically significant change (i.e. a decrease of at least 2 points) at day 7 or day 42, respectively, as compared with that of day 0. Change in pruritus and size of the hives significantly correlated with the change in the score of the quality of life. One-third of patients experienced complete relief whereas in 1 of 10 patients no effect was experienced.

CONCLUSIONS

Desloratadine significantly improves the quality of life of patients with chronic idiopathic urticaria as reflected by the dermatology life quality index (DLQI).

Urticaria: selected highlights and recent advances

Urticaria has been called a vexing problem and remains so today. The most important part of the diagnostic evaluation remains a comprehensive and detailed history and physical examination, supplemented with limited laboratory testing. Although acute urticaria has been relatively well understood for some time, significant and important recent advances in under-standing the pathogenesis of chronic urticaria are beginning to provide insight in this challenging field, notably the identification of many of these patients with an autoimmune etiology. Antihistamines of various types continue to represent the keystone of symptomatic treatment, with adjunctive support from medications of other classes, such as antileukotrienes, adrenergics, and immunosuppressive and anti-inflammatory agents (including steroids and cyclosporine). Although some progress has been made at improving symptomatic control of urticaria, further research and discovery are necessary before there can yet be an effective impact on the underlying course and natural history of this condition.

Central effects of fexofenadine and cetirizine: measurement of psychomotor performance, subjective sleepiness, and brain histamine H1-receptor occupancy using 11C-doxepin positron emission tomography

Histamine H1-receptor (H1R) antagonists, or antihistamines, often induce sedative side effects when used for the treatment of allergic disorders. This study compared the sedative profiles of the second-generation antihistamines, fexofenadine and cetirizine, using 3 different criteria: subjective sleepiness evaluated by the Stanford Sleepiness Scale, objective psychomotor tests (simple and choice reaction time tests and visual discrimination tests at 4 different exposure durations), and measurement of histamine H1-receptor occupancy (H1RO) in the brain. Subjective sleepiness and psychomotor performance were measured in 20 healthy Japanese volunteers at baseline and 90 min after administration of fexofenadine 120 mg or cetirizine 20 mg in a double-blind, placebo-controlled crossover study. Hydroxyzine 30 mg was included as a positive control. H1RO was measured using positron emission tomography (PET) with (11)C-doxepin in 12 of the 20 subjects, and a further 11 volunteers were recruited to act as controls. In psychomotor tests, fexofenadine was not significantly different from placebo and significantly less impairing than cetirizine on some tasks, as well as significantly less impairing than hydroxyzine on all tasks. For subjective sleepiness, fexofenadine was not significantly different from placebo, whereas cetirizine showed a trend toward increased sleepiness compared with fexofenadine and placebo. H1RO was negligible with fexofenadine (-0.1%) but moderately high with cetirizine (26.0%). In conclusion, fexofenadine 120 mg is distinguishable from cetirizine 20 mg, as assessed by H1RO and psychomotor testing.

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.

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.

Comparative efficacy of cetirizine and fexofenadine in the treatment of chronic idiopathic urticaria

OBJECTIVES

Antihistamines are the first line of therapy for chronic idiopathic urticaria (CIU). The present study was designed considering the lack of reports comparing the efficacy and safety of commonly prescribed cetirizine and fexofenadine in the treatment of CIU.

METHODS

A total of 116 patients, aged 17 to 65 years, with CIU (urticarial wheals for at least two days per week for six consecutive weeks before entry) were enrolled in this randomised double-blind study. Study period was 28 days with patient visits on days 14 and 28 for investigator evaluation of the clinical response. Patient evaluation was on the basis of an analogue scale. Final response to treatment was judged as symptom free, partial improvement, and no improvement.

RESULTS

Ninety-seven patients (52 cetirizine, 45 fexofenadine) completed the study. The response to treatment in both the groups at the end of treatment period was as follows; symptom free [cetirizine 27(51.9%), fexofenadine 2(4.4%)], partial improvement [cetirizine 19(36.5%), fexofenadine 19(42.2%)], no improvement [cetirizine 6(11.5%), fexofenadine 24(53.3%)]. Side effects noted were mild with no significant difference between the two.

CONCLUSION

Cetirizine seems to have therapeutic advantage over fexofenadine in the treatment of CIU.

Chronic urticaria: impact of allergic inflammation

Urticaria is defined by weals (hives), with or without angioedema, that appear and peak in minutes to hours, usually disappear within 24 h, and are accompanied by pruritus that worsens during the night. Urticaria is caused by cutaneous mast cell degranulation, attributed to immunological, nonimmunological, and idiopathic causes. Chronic idiopathic urticaria (CIU) is the diagnosis when the pathophysiological mechanism of persistent urticaria remains unclear; up to half of patients with CIU have functional autoantibodies directed against the high-affinity receptor for IgE (FcepsilonRI) or against IgE itself, which appear to induce mast cell degranulation. Systemic histamine H1-receptor antagonists, such as desloratadine, are central to the management of CIU. The efficacy and safety of desloratadine, 5 mg once daily, was studied in a double-blind, randomized, placebo-controlled, multicentre trial that included 190 patients, ages 12 and above, with at least a 6-week history of CIU and experiencing a flare of at least moderate severity. Desloratadine was superior to placebo in controlling pruritus and total symptoms after the first dose, and its superiority was maintained throughout the full 6 weeks of the study. Measures of sleep, daily activity, therapeutic response, and global CIU status were also significantly improved with desloratadine after the first dose and maintained throughout the study.

Pruritic dermatoses: overview of etiology and therapy

This review begins with a brief survey of the neurophysiology and neuroanatomy of pruritus, and goes on to describe the etiology of the major allergic and nonallergic pruritic disorders. The etiology of pruritus often suggests the appropriate treatment. For example, urticaria, which is primarily mediated by histamine, is amenable to treatment with H1 antihistamines. Second-generation, nonsedating antihistamines appear to be more effective than sedating antihistamines, perhaps because of better compliance. Other systemic pharmacologic options may be useful in nonhistamine-mediated disorders, for example, immunomodulators for inflammation-induced pruritus or opiate antagonists for atopic dermatitis. Nonpharmacologic measures, such as proper skin care, and physical modalities, such as phototherapy or acupuncture, may also be helpful.

Comparison of the efficacy of combined fluticasone propionate and olopatadine versus combined fluticasone propionate and fexofenadine for the treatment of allergic rhinoconjunctivitis induced by conjunctival allergen challenge

BACKGROUND

One approach to treating allergic rhinoconjunctivitis is the concomitant use of an intranasal spray such as fluticasone propionate to alleviate nasal symptoms and a topical or systemic agent to relieve ocular symptoms. It has not yet been determined whether a topical or systemic agent is more effective for the latter purpose.

OBJECTIVE

This study compared the efficacy of combined use of fluticasone and olopatadine with combined use of fluticasone and fexofenadine in the treatment of the signs and symptoms of allergic rhinoconjunctivitis.

METHODS

This 2-site, randomized, double-masked, placebo-controlled, parallel-group study employed the conjunctival allergen challenge (CAC) model, a standardized method of inducing ocular and nasal signs and symptoms of allergic rhinoconjunctivitis. At visit 1, subjects underwent CAC to determine the dose of allergen required to elicit a positive reaction. The allergen dose was confirmed at visit 2, and, according to a randomization schedule, subjects were dispensed fluticasone, olopatadine, and placebo pill; fluticasone, fexofenadine, and tear substitute; or placebo nasal spray, placebo pill, and tear substitute. CAC took place at visit 3, after patients had used the assigned medications for 2 weeks. Study medication was instilled 2 hours before CAC, after which allergic signs and symptoms were graded on standardized scales. The primary efficacy variables were ocular itching, ocular redness, and overall nasal symptoms.

RESULTS

Eighty subjects completed the study: 30 received fluticasone and olopatadine, 30 fluticasone and fexofenadine, and 20 placebo. Women constituted 63.8% of the study population and men 36.3%; 91.3% were white, 3.8% black, 2.5% Hispanic, 1.3% Asian, and 1.3% other. Concomitant use of fluticasone and olopatadine produced significantly greater improvements in ocular itching at 3 and 7 minutes after CAC compared with fluticasone and fexofenadine (P < 0.05). There were no significant differences in redness scores between groups; however, concomitant use of fluticasone and olopatadine produced significantly greater improvements in redness at 2 time points in each of the 3 vessel beds (ciliary, conjunctival, and episcleral) compared with placebo, and fluticasone and fexofenadine produced significantly greater improvement in redness at 1 time point in I vessel bed compared with placebo (both comparisons, P < 0.05). The 2 treatments had similar effects on total nasal symptom efficacy scores.

CONCLUSIONS

In this study, concomitant use of the topical agents fluticasone and olopatadine was more effective than concomitant use of fluticasone plus fexofenadine for overall treatment of the signs and symptoms of induced allergic rhinoconjunctivitis.