Allergic Rhinitis: A Review.

Importance: Allergic rhinitis affects an estimated 15% of the US population (approximately 50 million individuals) and is associated with the presence of asthma, eczema, chronic or recurrent sinusitis, cough, and both tension and migraine headaches. Observations: Allergic rhinitis occurs when disruption of the epithelial barrier allows allergens to penetrate the mucosal epithelium of nasal passages, inducing a T-helper type 2 inflammatory response and production of allergen-specific IgE. Allergic rhinitis typically presents with symptoms of nasal congestion, rhinorrhea, postnasal drainage, sneezing, and itching of the eyes, nose, and throat. In an international study, the most common symptoms of allergic rhinitis were rhinorrhea (90.38%) and nasal congestion (94.23%). Patients with nonallergic rhinitis present primarily with nasal congestion and postnasal drainage frequently associated with sinus pressure, ear plugging, muffled sounds and pain, and eustachian tube dysfunction that is less responsive to nasal corticosteroids. Patients with seasonal allergic rhinitis typically have physical examination findings of edematous and pale turbinates. Patients with perennial allergic rhinitis typically have erythematous and inflamed turbinates with serous secretions that appear similar to other forms of chronic rhinitis at physical examination. Patients with nonallergic rhinitis have negative test results for specific IgE aeroallergens. Intermittent allergic rhinitis is defined as symptoms occurring less than 4 consecutive days/week or less than 4 consecutive weeks/year. Persistent allergic rhinitis is defined as symptoms occurring more often than 4 consecutive days/week and for more than 4 consecutive weeks/year. Patients with allergic rhinitis should avoid inciting allergens. In addition, first-line treatment for mild intermittent or mild persistent allergic rhinitis may include a second-generation H1 antihistamine (eg, cetirizine, fexofenadine, desloratadine, loratadine) or an intranasal antihistamine (eg, azelastine, olopatadine), whereas patients with persistent moderate to severe allergic rhinitis should be treated initially with an intranasal corticosteroid (eg, fluticasone, triamcinolone, budesonide, mometasone) either alone or in combination with an intranasal antihistamine. In contrast, first-line therapy for patients with nonallergic rhinitis consists of an intranasal antihistamine as monotherapy or in combination with an intranasal corticosteroid. Conclusions and Relevance: Allergic rhinitis is associated with symptoms of nasal congestion, sneezing, and itching of the eyes, nose, and throat. Patients with allergic rhinitis should be instructed to avoid inciting allergens. Therapies include second-generation H1 antihistamines (eg, cetirizine, fexofenadine, desloratadine, loratadine), intranasal antihistamines (eg, azelastine, olopatadine), and intranasal corticosteroids (eg, fluticasone, triamcinolone, budesonide, mometasone) and should be selected based on the severity and frequency of symptoms and patient preference.

Intranasal combo: fixed-dose combination of mometasone furoate and olopatadine hydrochloride in therapeutic strategies for rhinosinusitis.

A novel strategy for the treatment of allergic rhinitis results from the innovative combination of antihistamine and intranasal corticosteroid drugs. By combining two preparations with different mechanism of action, this novel approach facilitates quick and effective controls of all upper respiratory tract allergy symptoms. The article presents the results of a study of olopatadine hydrochloride and mometasone furoate fixed-dose combination (GSP301) administered intranasally from a spray formulation, with an attempt at positioning the treatment within the ARIA and EPOS guidelines.

Efficacy of Alcaftadine 0.25% (AGN-229666) for Once-daily Prevention of Cedar-Pollen Allergic Conjunctivitis: A Phase 3 Randomized Study.

Purpose: This study evaluated the efficacy and safety of once-daily Alcaftadine 0.25% (AGN-229666) for prevention of signs and symptoms of Japanese cedar-pollen allergic conjunctivitis.Methods: This was a single-center, placebo-, and comparator-controlled study using the Ora-CAC® model of allergic conjunctivitis. The primary endpoint was ocular itching 16 hours after Alcaftadine 0.25% instillation; efficacy at 16 hours was compared with 0.1% Olopatadine, 4 hours after instillation. Secondary endpoints included conjunctival hyperemia.Results: 263 Japanese subjects were enrolled; 224 completed the trial. Alcaftadine 0.25% was statistically superior to vehicle for relief of ocular itching at 16 hours (p < .0001). Alcaftadine 0.25% at 16 hours was non-inferior to Olopatadine at 4 hours. Alcaftadine 0.25% was significantly better than vehicle for relief of conjunctival hyperemia. All treatments showed a low frequency of ocular adverse events.Conclusion: Once-daily Alcaftadine 0.25% is safe and effective in preventing signs and symptoms of Japanese cedar-pollen allergic conjunctivitis.

Pupil Diameter, Corneal Thickness, and Anterior Chamber Alterations Following Topical Olopatadine Hydrochloride 0.1%: A Single-Masked Randomized Controlled Clinical Study.

Purpose: Olopatadine hydrochloride 0.1% is one of the known primary topical treatments in ocular allergy. Although olopatadine is a worldwide used medication, the changes in pupil diameter, cornea, and anterior chamber associated with its use have not been studied in detail. In this prospective study, we aimed to determine the amount of mydriasis and explore the possible corneal and anterior chamber alterations after 0.1% topical olopatadine. Methods: A total of 77 eyes from 77 ocular-allergy diagnosed patients between 18 and 40 years were investigated in this prospective study. Thirty-nine eyes of 39 patients received topical olopatadine, and 38 eyes of 38 patients received sterile distilled water, randomly. Pentacam (Oculus Optikgeräte GmbH, Wetzlar, Germany) topography was used to assess the pupil and anterior chamber measurements at baseline and after 45 min of olopatadine or sterile distilled water instillation. Results: The differences between the baseline and 45th-min measurements for corneal thickness, anterior chamber depth, angle, and volume did not reach a statistical significance in the olopatadine or control groups. The pupil diameter significantly increased from 3.19 ± 0.62 to 3.36 ± 0.62 mm in the olopatadine group (P < 0.001), and remained relatively unchanged in the control group (P = 0.06). Conclusion: Olopatadine 0.1% does not lead to a significant change in corneal topography or anterior chamber parameters. However, it causes a slight but statistically significant increase in pupil diameter.

To evaluate the efficacy and safety of olopatadine 0.1% ophthalmic solution and bepotastine 1.5% ophthalmic solution in patients with vernal keratoconjunctivitis in a tertiary care hospital.

INTRODUCTION: Vernal conjunctivitis comprises 0.5% of allergic eye diseases. The study is intended to collate the effectiveness of drugs by observing the reduction in signs and symptoms. OBJECTIVES: The objective of the study is to evaluate the effectiveness and safety of olopatadine 0.1% ophthalmic drops with bepotastine besilate 1.5% ophthalmic drops in patients with vernal keratoconjunctivitis (VKC). MATERIALS AND METHODS: A randomized, open-label, comparative study conducted in Sarojini Devi Eye Hospital, Telangana. The study included 50 patients diagnosed with VKC, of which Group A and Group B were given olopatadine 0.1% ophthalmic drops and bepotastine besilate 1.5% ophthalmic drops, respectively, twice a day for 8 weeks. The reduction in signs and symptoms in both groups was compared. The observations and results were tabulated accordingly, and data were analyzed using the SPSS. The unpaired t-test is used as the test of significance in between two groups. P value is statistically significant when it is less than 0.05. RESULTS: Overall, 50 cases were included in the study, 72% of total patients were in the age group of 5-10 years, and 28% were in the age group of 11-15 years. There were 39 males and 11 females. After 8 weeks of follow-up, the mean reduction in the scoring of symptoms and signs provided better and quicker relief of watering, ocular discomfort, and conjunctival hyperemia with bepotastine 1.5% eye drops. Olopatadine 0.1% eye drops provided faster improvement in papillary hypertrophy. Both drugs were equally effective in reducing itching. Laboratory findings of absolute eosinophil count had no statistical significance in between the two groups. CONCLUSIONS: In this study, based on the evaluation of therapeutic performance, bepotastine eye drops proved quicker relief of symptoms and signs compared to olopatadine eye drops but was not statistically significant which would prove beneficial for the patients.

Efficacy and safety of twice-daily and once-daily olopatadine-mometasone combination nasal spray for seasonal allergic rhinitis.

BACKGROUND: GSP301 is an investigational fixed-dose combination nasal spray of olopatadine hydrochloride (antihistamine) and mometasone furoate (corticosteroid). OBJECTIVE: To evaluate efficacy and safety of GSP301 in patients with seasonal AR (SAR). METHODS: In this phase 2, double-blind, parallel-group study, patients (≥12 years of age) with SAR were equally randomized to twice-daily GSP301 (olopatadine 665 µg and mometasone 25 µg), once-daily GSP301 (olopatadine 665 µg and mometasone 50 µg), twice-daily or once-daily olopatadine monotherapy (665 µg), mometasone monotherapy (twice-daily 25 µg or once-daily 50 µg), or placebo for 14 days. The primary endpoint-mean change from baseline in morning and evening reflective Total Nasal Symptom Score (rTNSS)-was analyzed using analysis of covariance (ANCOVA; P < .05 = statistically significant). Average morning and evening 12-hour instantaneous TNSS (iTNSS), ocular symptoms, individual symptoms, onset of action, quality of life, and adverse events (AEs) were also assessed. RESULTS: A total of 1111 patients were randomized. Twice-daily GSP301 provided statistically significant and clinically meaningful rTNSS improvements vs placebo (P < .001), twice-daily olopatadine (P = .049), and mometasone (P = .004). Similar significant improvements in iTNSS were observed with twice-daily GSP301 vs placebo (P < .001) and twice-daily mometasone (P = .007); improvements were not significant vs olopatadine (P = .058). Once-daily GSP301 provided significant rTNSS and iTNSS improvements vs placebo and once-daily olopatadine (P < .01, all) but improvements were not significant vs mometasone. Treatment-emergent AEs rates were 10.8%, 9.5%, and 8.2%, with twice-daily GSP301, once-daily GSP301, and placebo, respectively. CONCLUSION: Twice-daily GSP301 treatment was efficacious and well tolerated, providing statistically significant and clinically meaningful improvements in rTNSS (primary endpoint) vs placebo and both monotherapies. TRIAL REGISTRATION: Clinicaltrials.gov Identifier NCT02318303.

Recurrent immediate type hypersensitivity reaction induced by macrogol in a 3-year-old Boy

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Observer-masked trial comparing efficacy of topical olopatadine (0.1%), bepotastine (1.5%), and alcaftadine (0.25%) in mild to moderate allergic conjunctivitis.

Purpose: With increasing environmental pollution, the incidence of allergic conjunctivitis is increasing. Newer anti-allergic medications with combined anti-histaminic and mast cell stabilization action can help reducing the use of topical steroids for milder form of disease. There is no study directly comparing olopatadine (0.1%), bepotastine (1.5%), and alcaftadine (0.25%) for mild to moderate allergic conjunctivitis cases. Hence, we decided to methodically study the efficacy of three topical medications. Methods: Prospective, observer-masked clinical trial enrolled 45 patients with 15 patients in each of the three groups. Patients with mild to moderate allergic conjunctivitis were sequentially assigned to respective groups, and relief of symptoms and signs were noted upto 1-month follow-up. Results: All three topical medications faired almost equally in resolving symptoms of the patients with mild to moderate allergic conjunctivitis, and most of them reported complete relief after 1 week of use of medication. Few cases with limbal or palpebral papillae reported symptomatic relief after use of medication, but the resolution of these signs was not noted in all three groups. Conclusion: We concluded similar efficacy of three medications in relieving symptoms and inefficacy in regressing palpebral and limbal papillae in cases of allergic conjunctivitis.

The histaminergic control of the iridal vascular tone in rats and its influencing by topical administration of olopatadine and ranitidine.

Objective. We evaluated the histamine's role in regulating the iris vasomotricity in rats, using as a research tool topical olopatadine, a selective H1 blocker, which is indicated for the treatment of allergic conjunctivitis and ranitidine, a selective H2 blocker mainly used for the treatment of peptic ulcer disease. Methods. Two groups of six Wistar rats anesthetized with ketamine 200 mg/kg body weight were used. They received distilled water in conjunctival instillations, initially and after 5 minutes, olopatadine 2.5 mmol/ l for the first group, respectively ranitidine 2.5 mmol/ l for the second group. The changes of the iris arteriolar and venular diameters were recorded. Results. Both olopatadine and ranitidine produced statistically significant iridal arteriolar vasoconstriction and ranitidine determined statistically significant venuloconstriction, while distilled water did not produce any statistically significant effect. Conclusions. There is a vasodilator histaminergic tone exerted through the histaminergic H1 and H2 receptors in the iris arterioles and, respectively, through the H2 receptors in the iridal venules. Olopatadine, a topical H1 antagonist used in the treatment of ocular allergies, may interfere with the humoral regulation of the iris arteriolar tone. Ranitidine, an H2 antagonist, decreased the diameter of the iris arterioles and venules, when administered topically in rats.

Alcaftadine 0.25% versus Olopatadine 0.1% in Preventing Cedar Pollen Allergic Conjunctivitis in Japan: A Randomized Study.

Purpose: To compare alcaftadine and olopatadine ophthalmic solutions, and vehicle for preventing allergen-mediated conjunctivitis in Japanese subjects. Methods: Japanese cedar pollen-sensitive subjects were randomized to alcaftadine 0.25%, olopatadine 0.1%, or vehicle. Ocular itching was assessed at 3, 5 (primary outcome), 7, and 15 min post-conjunctival allergen challenge (CAC) and conjunctival hyperemia assessed at 7, 15 (secondary outcome), and 20 min post-CAC. Adverse events were monitored. Results: Overall, 240 subjects were randomized. Alcaftadine 0.25% (challenged 8 h post-dose) was significantly more effective than vehicle for prevention of itching and conjunctival hyperemia (p < 0.001) and noninferior to olopatadine 0.1% (challenged 4 h post-dose). Significantly lower hyperemia scores were observed in alcaftadine-treated than olopatadine-treated eyes at 7 and 15 min post-CAC (p ≤ 0.027). Alcaftadine and olopatadine were well tolerated; no serious adverse events were reported. Conclusion: Alcaftadine 0.25% is effective in preventing signs and symptoms of Japanese cedar pollen-induced allergic conjunctivitis.

Effect of olopatadine-mometasone combination nasal spray on seasonal allergic rhinitis symptoms in an environmental exposure chamber study.

BACKGROUND: GSP301 nasal spray is a fixed-dose combination of the antihistamine olopatadine hydrochloride and the corticosteroid mometasone furoate intended for seasonal allergic rhinitis (SAR) treatment. OBJECTIVE: To evaluate the efficacy and safety of once-daily or twice-daily GSP301 in a ragweed pollen environmental exposure chamber. METHODS: In this randomized, double-blind, double-dummy study, adults (18-65 years old) with SAR were equally randomized to 665 µg of olopatadine and 25 µg of mometasone (twice-daily GSP301), 665 µg of olopatadine and 50 µg of mometasone (once-daily GSP301), a US Food and Drug Administration-approved formulation of 137 µg of azelastine and 50 µg of fluticasone twice-daily (AzeFlu), a US Food and Drug Administration-approved formulation of 665 µg of olopatadine twice-daily, or placebo (twice-daily). During 2 visits (baseline and end of 14-day treatment), participants assessed SAR symptoms at specified time points. The primary end point-mean change from baseline in instantaneous total nasal symptom score (iTNSS) for twice-daily or once-daily GSP301 vs placebo-was analyzed by analysis of covariance. Onset of action, ocular symptoms, and adverse events were assessed. RESULTS: A total of 180 participants were randomized. Treatment with twice-daily or once-daily GSP301 provided statistically significant improvements in iTNSS vs placebo (twice-daily GSP301: least squares mean difference, -3.60; 95% confidence interval [CI], -4.89 to -2.30; once-daily GSP301: least squares mean difference, -3.05; 95% CI, -4.35 to -1.76; P < .0001 for both). Significant improvements in iTNSS with twice-daily GSP301 occurred by 10 minutes after dosing (-1.26; 95% CI, -2.30 to -0.21; P = .02) and were maintained at all later time points except one (2.5 hours). Treatment-emergent adverse events occurred in 22.2%, 30.6%, 25.0%, 22.2%, and 16.7% of participants in the twice-daily GSP301, once-daily GSP301, AzeFlu, olopatadine, and placebo groups, respectively. CONCLUSION: In an environmental exposure chamber model, twice-daily and once-daily GSP301 treatments were well tolerated and provided statistically significant and clinically meaningful SAR symptom improvement vs placebo. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03444506.

Optimization of a novel in situ gel for sustained ocular drug delivery using Box-Behnken design: In vitro, ex vivo, in vivo and human studies.

The aim of the present research work was to formulate, optimize and evaluate the in-situ gel for the ophthalmic drug delivery using the combination of gellan gum and carbopol 934P. The Box-Behnken design was applied to optimize the concentration of gellan gum (X1), carbopol 934P (X2) and benzododecenium bromide (X3) to achieve the maximum viscosity [at physiological condition; 35 °C, pH 7.4, and simulated tear fluid (STF)], mucoadhesive strength, permeability coefficient and sustained release of the drug from the gel with constraint on the viscosity under the non-physiological condition (25 °C, pH 5). Response surface plots were drawn, the statistical validity of the polynomials was established, and optimized formulation was selected by the feasibility and grid search. The design proposed the optimized batch by selecting the independent variables as gellan gum (0.55% w/v), carbopol 934P (0.35% w/v) and benzododecenium bromide (0.013% w/v) to achieve the maximum viscosity (3363 cps) at physiological condition, mucoadhesive strength (22.35 dyn/cm2), t90% (1200 min), permeability coefficient (1.36 × 10-5 sq.cm/sec), with minimum viscosity (131 cps) under the non-physiological condition. The combination of gellan gum and carbopol 934P improved the gelation (synergistic effect) characteristics of the in situ gel. The optimized in situ gel was clear, isotonic, pH 4.7 and showed pseudoplastic flow, high in vitro gelling capacity, low contact angle, acceptable hardness (51018 gm), compressibility (64617 gm) and adhesiveness (74 gm) values for the ocular application. The ex vivo study showed the significant protection of the mast cell from the degranulation. The ocular irritation and histopathology studies in the rabbit eyes confirmed the safety of in situ gel for human use. The in vivo drug release studies showed the presence of drug in the rabbit tear fluid up to 3 h in comparison to just 1 h with the eye drop solution. The contact time of the in situ gel in the human eye was 15.0 ±â€¯2.5 min, which was >2 folds higher than the marketed gel (6.0 ±â€¯3.2 min), which could reduce the dosing frequency and total dose of drug. The Box-Behnken design facilitated the optimization of in situ gel for sustained ophthalmic drug delivery.

Projected 24-hour post-dose ocular itching scores post-treatment with olopatadine 0.7% versus 0.2.

Olopatadine is an antihistamine and mast cell stabilizer used for treating allergic conjunctivitis. Olopatadine 0.7% has been recently approved for daily dosing in the US, which supersedes the previously approved 0.2% strength. The objective of this analysis was to characterize patients who have better itching relief at 24 h when taking olopatadine 0.7% treatment instead of olopatadine 0.2% (in terms of proportions of responses) and relate this to the severity of baseline itching as an indirect metric of a patient's sensitivity to antihistamines. A differential odds model was developed using data from two conjunctival allergen challenge (CAC) studies to characterize individual-level and population-level response to ocular itching following olopatadine treatment and the data was analyzed retrospectively. This modeling analysis was designed to predict 24 h ocular itching scores and to quantify the differences in 24 h itching relief following treatment with olopatadine 0.2% versus 0.7% in patients with moderate-to-high baseline itching. A one-compartment kinetic-pharmacodynamic Emax model was used to determine the effect of olopatadine. Impact of baseline itching severity, vehicle effect and the drug effect on the overall itching scores post-treatment were explicitly incorporated in the model. The model quantified trends observed in the clinical data with regards to both mean scores and the proportions of patients responding to olopatadine treatment. The model predicts a higher proportion of patients in the olopatadine 0.7% versus 0.2% group will experience relief within 24 h. This prediction was confirmed with retrospective clinical data analysis. The number of allergy patients relieved with olopatadine 0.7% increased with higher baseline itching severity scores, when compared to olopatadine 0.2%.

Olopatadine hydrochloride ophthalmic solution for the treatment of allergic conjunctivitis.

INTRODUCTION: Olopatadine hydrochloride is an antihistamine and mast cell stabilizer available as oral, intranasal and ocular preparations. Most of the practical applications of olopatadine therapy focus on the treatment of allergic rhinoconjunctivitis via intranasal and ocular routes. Areas covered: This article was created from a comprehensive literature search with information taken from meta-analyses, systematic reviews, and clinical trials of children and adults. The articles that have been selected, evaluate the use of intranasal and ocular antihistamines and their role in allergic rhinoconjunctivitis. Expert opinion: Olopatadine is significantly more effective than placebos in relieving the symptoms of allergic rhinoconjunctivitis. It can function both as a viable alternative or addition to first line therapies such as intranasal steroids and oral antihistamines.

Citric Acid Suppresses the Bitter Taste of Olopatadine Hydrochloride Orally Disintegrating Tablets.

Orally disintegrating tablets (ODTs) are formulated to disintegrate upon contact with saliva, allowing administration without water. Olopatadine hydrochloride, a second-generation antihistamine, is widely used for treating allergic rhinitis. However, it has a bitter taste; therefore, the development of taste-masked olopatadine ODTs is essential. Some studies have suggested that citric acid could suppress the bitterness of drugs. However, these experiments were performed using solutions, and the taste-masking effect of citric acid on ODTs has not been evaluated using human gustatory sensation tests. Thus, this study evaluated citric acid's taste-masking effect on olopatadine ODTs. Six types of olopatadine ODTs containing 0-10% citric acid were prepared and subjected to gustatory sensation tests that were scored using the visual analog scale. The bitterness and overall palatability of olopatadine ODTs during disintegration in the mouth and after spitting out were evaluated in 11 healthy volunteers (age: 22.8±2.2 years). The hardness of the ODTs was >50 N. Disintegration time and dissolution did not differ among the different ODTs. The results of the gustatory sensation tests suggest that citric acid could suppress the bitterness of olopatadine ODTs in a dose-dependent manner. Olopatadine ODTs with a high content of citric acid (5-10%) showed poorer overall palatability than that of those without citric acid despite the bitterness suppression. ODTs containing 2.5% citric acid, yogurt flavoring, and aspartame were the most suitable formulations since they showed low bitterness and good overall palatability. Thus, citric acid is an effective bitterness-masking option for ODTs.

[Eye lid hygiene in chronic allergic blepharoconjunctivitis patients before laser refractive surgery]. / Gigiena vek v podgotovke k lazernoi refraktsionnoi khirurgii.

AIM: To evaluate the effectiveness of eyelid hygiene in patients with chronic allergic blepharoconjunctivitis (ABC) as a part of their preparation for laser refractive surgery. MATERIAL AND METHODS: The study involved 32 patients (12 males and 20 females aged 25-42 years) with refractive errors, namely, compound myopic astigmatism (23 patients) and hyperopic astigmatism (9 patients) suffering from chronic ABC and secondary dry eye syndrome (DES). All the patients initially received a standard treatment for ABC and DES, that is olopatodin hydrochloride instillations - 1 mg/ml 2 times daily, preservative-free hyaluronic acid preparation - 1 mg/ml 3 times daily, and polyacrylic acid and dexpanthenol gel at night for one month. The scheme, however, appeared not effective enough. Hence, the patients were prescribed eyelid hygiene (Blepharolotion or Blepharosalfetka plus Blepharogel-1 2 times daily) to relive meibomian gland dysfunction (MGD). They also underwent a conventional ophthalmic examination, allergy tests, evaluation of ABC and DES signs and symptoms, tear film break-up time test, Schirmer's test, meibomian glands evaluation, optical coherence tomography with meniscometry, xerosis index evaluation, and lissamine green staining for lid wiper epitheliopathy. RESULTS: At the beginning of the study signs and symptoms of MGD-associated DES were predominant in all patients. Chronic ABC signs were mild. In 2-3 months, meibomian gland function and tear film break-up time improved significantly in most patients, while xerosis index decreased and lid wiper epitheliopathy resolved. Laser refractive surgery (LASIK) was performed in 81.25% of patients, all of whom were satisfied with the results. CONCLUSION: Inclusion of eyelid hygiene into preoperative management of patients with chronic ABC and DES allows to achieve optimum conditions for laser refractive surgery in most cases.

Olopatadine hydrochloride suppresses hot flashes induced by topical treatment with tacrolimus ointment in rats.

Tacrolimus ointment is prescribed for patients with atopic dermatitis, although it is known to cause transient burning sensations and hot flashes in the applied skin. The aim of this study was to evaluate the effects of olopatadine hydrochloride (olopatadine), an antiallergic agent with a histamine H1 receptor (H1R) antagonistic activity, on the incidence of hot flashes induced by topical treatment with tacrolimus ointment in rats. Consequently, the skin temperature was increased by the topical application of tacrolimus ointment in rats, and the rise in skin temperature was inhibited by pretreatment with olopatadine in a dose-dependent manner. Inhibitory effect of olopatadine on tacrolimus-induced skin temperature elevation was significantly more potent than that of cetirizine hydrochloride, other antiallergic agent with H1R antagonistic activity, at doses in which both agents exhibit comparable H1R antagonistic activity in rats. These results suggest that H1R antagonistic activity-independent mechanism contribute to the inhibitory effect of olopatadine on tacrolimus-induced skin temperature elevation. Olopatadine also significantly inhibited increases in vascular permeability and nerve growth factor production in the skin induced by topical tacrolimus treatment. Thus, the onset of hot flashes in rats is quantitatively determined by measuring the skin temperature and olopatadine attenuates hot flashes induced by topical tacrolimus ointment in rats, suggesting that the combination application with olopatadine and tacrolimus ointment is useful for improving medication adherence with tacrolimus ointment treatment in patients with atopic dermatitis.