Leukotriene receptor antagonists as add-on therapy to antihistamines for urticaria: Systematic review and meta-analysis of randomized clinical trials.

BACKGROUND: The benefits and harms of adding antileukotrienes to H1 antihistamines (AHs) for the management of urticaria (hives, itch, and/or angioedema) remain unclear. OBJECTIVE: We sought to systematically synthesize the treatment outcomes of antileukotrienes in combination with AHs versus AHs alone for acute and chronic urticaria. METHODS: As part of updating American Academy of Allergy, Asthma & Immunology and American College of Allergy, Asthma, and Immunology Joint Task Force on Practice Parameters urticaria guidelines, we searched Medline, Embase, Central, LILACS, WPRIM, IBECS, ICTRP, CBM, CNKI, VIP, Wanfang, US Food and Drug Administration, and European Medicines Agency databases from inception to December 18, 2023, for randomized controlled trials (RCTs) evaluating antileukotrienes and AHs versus AHs alone in patients with urticaria. Paired reviewers independently screened citations, extracted data, and assessed risk of bias. Random effects models pooled effect estimates for urticaria activity, itch, wheal, sleep, quality of life, and harms. The GRADE approach informed certainty of evidence ratings. The study was registered at the Open Science Framework (osf.io/h2bfx/). RESULTS: Thirty-four RCTs enrolled 3324 children and adults. Compared to AHs alone, the combination of a leukotriene receptor antagonist with AHs probably modestly reduces urticaria activity (mean difference, -5.04; 95% confidence interval, -6.36 to -3.71; 7-day urticaria activity score) with moderate certainty. We made similar findings for itch and wheal severity as well as quality of life. Adverse events were probably not different between groups (moderate certainty); however, no RCT reported on neuropsychiatric adverse events. CONCLUSION: Among patients with urticaria, adding leukotriene receptor antagonists to AHs probably modestly improves urticaria activity with little to no increase in overall adverse events. The added risk of neuropsychiatric adverse events in this population with leukotriene receptor antagonists is small and uncertain.

Leukotriene receptor antagonists as adjuvant therapy of antihistamines in chronic urticaria: a systematic review and meta-analysis.

Certain guidelines recommend a second-generation H1-antihistamine (AH) as first-line treatment for patients with chronic urticaria (CU). However, some patients show insufficient response to a standard dose of this therapy and might benefit from adding leukotriene receptor antagonists (LTA). Therefore, we aimed to perform a systematic review and meta-analysis comparing LTA plus antihistamines with antihistamines alone. We performed a systematic review and meta-analysis, searching PubMed, EMBASE, and Cochrane Central for randomized clinical trial (RCT) data comparing LTA plus AH treatment to AH alone in patients with CU. Statistical analysis was performed using R Studio 4.3.2. Heterogeneity was assessed with I2 statistics. Three studies comprising 234 patients with urticaria were included. The mean age was 37.23 years in the leukotriene antagonist + antihistamines (LTA + AH) group and 39.14 years in the antihistamines (AH) group. Follow-up ranged from 2 to 18 months between studies. There was no statistically significant difference between groups in terms of TSS level (SMD: -74.82; 95% CI: -222.66 to 73.02; P = 0.32; I2 = 98%), neither in terms of pruritus (MD: -0.07; 95% CI: -0.42 to 0.28; P = 0.70; I2 = 74%). After sensitivity analysis, with the systematic exclusion of each study from the grouped estimates, the result for TSS level did not change. These findings suggest that leukotriene receptor antagonists with antihistamines do not have better outcomes than antihistamines alone regarding TSS and pruritus in patients with CU.

The anti-seizure potential of cysteine leukotriene receptor antagonists: A systematic review of animal studies.

BACKGROUND: Emerging literature has suggested the antiepileptic activity of cysteine leukotriene receptor (CysLTR) antagonists in experimental animals of epilepsy. Leukotrienes are substances that cause inflammation and affect brain activity, blood flow, oxidation, and inflammation in the brain. These processes are related to epilepsy and its complications. CysLTR antagonists are drugs that prevent leukotrienes from working. They may be useful for treating epilepsy, especially for people who do not respond to other drugs. Therefore, the current study aims to systematically review the potential anti-seizure effect of CysLTR antagonists in experimental studies. METHOD: We systematically reviewed the online databases using online databases such as Google Scholar, science direct, and PubMed until December 2022 to identify experimental studies assessing the anti-seizure activity of CysLTR antagonists. The Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) was used to evaluate the risk of bias (RoB) of the included studies. RESULTS: Initially we identified 3823 studies. After screening using inclusion and exclusion criteria, 8 studies were finally included in the current study. All included studies, reported that CysLTR antagonists reduced the intensity of seizures in animal models of epilepsy. CONCLUSION: In conclusion, CysLTR antagonists could be a potential therapeutic approach for the treatment of epilepsy. However, further preclinical and clinical studies are required to confirm their efficacy, safety, and mechanism of anti-seizure activity.

The First-Line Approach in Children with Obstructive Sleep Apnea Syndrome (OSA).

Obstructive sleep apnea syndrome (OSA) is the main manifestation of sleep-disordered breathing in children. Untreated OSA can lead to a variety of complications and adverse consequences mainly due to intermittent hypoxemia. The pathogenesis of OSA is multifactorial. In children aged 2 years or older, adenoid and/or tonsil hypertrophy are the most common causes of upper airway lumen reduction; obesity becomes a major risk factor in older children and adolescents since the presence of fat in the pharyngeal soft tissue reduces the caliber of the lumen. Treatment includes surgical and non-surgical options. This narrative review summarizes the evidence available on the first-line approach in children with OSA, including clinical indications for medical therapy, its effectiveness, and possible adverse effects. Literature analysis showed that AT is the first-line treatment in most patients with adenotonsillar hypertrophy associated with OSA but medical therapy in children over 2 years old with mild OSA is a valid option. In mild OSA, a 1- to 6-month trial with intranasal steroids (INS) alone or in combination with montelukast with an appropriate follow-up can be considered. Further studies are needed to develop an algorithm that permits the selection of children with OSA who would benefit from alternatives to surgery, to define the optimal bridge therapy before surgery, to evaluate the long-term effects of INS +/- montelukast, and to compare the impact of standardized approaches for weight loss.

Adverse drug reactions affecting treatment adherence in first-line treatment of asthma: An observational study.

BACKGROUND: Asthma is the most common chronic lung disease among children. International guidelines recommend inhaled corticosteroids (ICS) as the first-line daily controller therapy for children with asthma and leukotriene receptor antagonists (LTRA) as the second alternative therapy. Adherence to treatment is the most significant component to optimize the benefits of therapy in asthma. OBJECTIVE: This study aims to investigate the frequency of drug discontinuation due to adverse drug reactions (ADRs) that affect adherence to treatment in children with asthma or asthma and allergic rhinitis using LTRA or ICS as monotherapy. METHODS: The subjects aged 4-18 years with asthma or asthma and allergic rhinitis and using montelukast or ICS as monotherapy were included in the study. They were evaluated in terms of ADRs affecting adherence to treatment in the first and third months of treatment. RESULTS: A total of 468 cases, 356 of whom received montelukast monotherapy and 112 of whom received ICS treatment, with a mean age of 9.10 ± 3.08 (4-17) years, were included in the study. Males constituted 65.6% of the total cases (n = 307). In the first month of follow-up of the cases, it was observed that 4.8% (n = 17) of the patients in the montelukast group could not continue the treatment due to ADR. It was determined that the drug discontinuation rate in the montelukast group in the first month was significantly higher than in the ICS group (P = 0.016), and the risk of drug discontinuation due to ADR in the montelukast group was 1.333 (95% CI, 1.26-1.40) times higher. CONCLUSIONS: As a result, it was observed that the drug was discontinued due to ADR at a higher rate in children with asthma who received montelukast monotherapy compared to those who received ICS monotherapy.

Adverse drug reactions affecting treatment adherence in first-line treatment of asthma: An observational study

Background: Asthma is the most common chronic lung disease among children. International guidelines recommend inhaled corticosteroids (ICS) as the first-line daily controller therapy for children with asthma and leukotriene receptor antagonists (LTRA) as the second alternative therapy. Adherence to treatment is the most significant component to optimize the benefits of therapy in asthma. Objective: This study aims to investigate the frequency of drug discontinuation due to adverse drug reactions (ADRs) that affect adherence to treatment in children with asthma or asthma and allergic rhinitis using LTRA or ICS as monotherapy. Methods: The subjects aged 4–18 years with asthma or asthma and allergic rhinitis and using montelukast or ICS as monotherapy were included in the study. They were evaluated in terms of ADRs affecting adherence to treatment in the first and third months of treatment. Results: A total of 468 cases, 356 of whom received montelukast monotherapy and 112 of whom received ICS treatment, with a mean age of 9.10 ± 3.08 (4–17) years, were included in the study. Males constituted 65.6% of the total cases (n = 307). In the first month of follow-up of the cases, it was observed that 4.8% (n = 17) of the patients in the montelukast group could not continue the treatment due to ADR. It was determined that the drug discontinuation rate in the montelukast group in the first month was significantly higher than in the ICS group (P = 0.016), and the risk of drug discontinuation due to ADR in the montelukast group was 1.333 (95% CI, 1.26–1.40) times higher. Conclusions: As a result, it was observed that the drug was discontinued due to ADR at a higher rate in children with asthma who received montelukast monotherapy compared to those who received ICS monotherapy (AU)

Montelukast Increased IL-25, IL-33, and TSLP via Epigenetic Regulation in Airway Epithelial Cells.

The epithelium-derived cytokines interleukin (IL)-25, IL-33, and thymic stromal lymphopoietin (TSLP) are important mediators that initiate innate type 2 immune responses in asthma. Leukotriene receptor antagonists (LTRAs) are commonly used to prevent asthma exacerbations. However, the effects of LTRAs on epithelium-derived cytokines expression in airway epithelial cells are unclear. This study aimed to investigate the effects of LTRAs on the expression of epithelium-derived cytokines in human airway epithelial cells and to explore possible underlying intracellular processes, including epigenetic regulation. A549 or HBE cells in air-liquid interface conditions were pretreated with different concentrations of LTRAs. The expression of epithelium-derived cytokines and intracellular signaling were investigated by real-time PCR, enzyme-linked immunosorbent assay, and Western blot. In addition, epigenetic regulation was investigated using chromatin immunoprecipitation analysis. The expression of IL-25, IL-33, and TSLP was increased under LTRAs treatment and suppressed by inhaled corticosteroid cotreatment. Montelukast-induced IL-25, IL-33, and TSLP expression were mediated by the mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) pathways and regulated by histone H3 acetylation and H3K36 and H3K79 trimethylation. LTRAs alone might increase inflammation and exacerbate asthma by inducing the production of IL-25, IL-33, and TSLP; therefore, LTRA monotherapy may not be an appropriate therapeutic option for asthma.

Is Leukotriene Receptor Antagonist the Direct Cause of Churg-Strauss Syndrome in Asthmatic Patients?

One of the main reasons for continuous, persistent asthma is when there is a change in the structure of the airways and the Lung parenchyma. These persistent changes bring a much worse prognosis to asthmatic conditions and predispose the situation to severe asthmatic syndromes such as Churg-Strauss syndrome (CSS). CSS is an inflammation of systemic blood vessels and is a rare disorder that can be suspected in long-standing asthmatic patients. Leukotriene antagonists receptor antagonists (LTRA) have been used to treat asthma along with tapering steroids. But after the introduction of LTRA therapy in these patients suggests a causal relation between LTRA initiation and the development of CSS, or it is an unmasking of CSS as the dose of steroid tapers down with LTRA therapy. This review highlights the relationship between leukotriene antagonists and the pathogenesis of CSS. It summarizes the current literature regarding the development of CSS with the initiation of LTRA therapy on asthmatic patients. The literature on this topic was reviewed using different research/article searches, manual library searches, conference abstracts, and internet searches.

Relationship Between Leukotriene Receptor Antagonists on Cancer Development in Patients With Bronchial Asthma: A Retrospective Analysis.

BACKGROUND/AIM: An association between leukotriene receptor antagonists (LTRA) and cancer has been previously reported, but the relationship between LTRA use and cancer prevention remains controversial. This study aimed to clarify the cancer-preventive effect of LTRA in Japanese patients with bronchial asthma. PATIENTS AND METHODS: We obtained information from a large populationbased medical information database to analyze data on patients who were newly diagnosed with bronchial asthma between 2006 and 2015. Eligible participants were patients who were prescribed an LTRA for at least 30 days (LTRA users) and those who were not using LTRA (LTRA non-users) during the objective period. LTRA users and LTRA non-users were matched 1:1 using propensity scores. RESULTS: The 1:1 propensity score matching of LTRA users and LTRA nonusers facilitated the inclusion of 3,744 participants each, in these two subgroups. The results of the Cox proportional hazards model after adjustment for covariates showed no significant difference in the cancer risk between LTRA users and non-users [adjusted hazard ratio (HR)=0.83, 95% confidence interval (CI)=0.59-1.16]. The subgroup analysis showed no significant difference in the cancer risk between the LTRA low-cumulative dose group and LTRA non-users, or between the LTRA medium-cumulative dose group and LTRA non-users. In contrast, the LTRA high-cumulative dose group had a significantly lower risk of developing cancer compared with LTRA non-users (adjusted HR=0.57, 95% CI=0.33-0.98). CONCLUSION: LTRA use may prevent cancer in patients with bronchial asthma.

The comparative effect of Leukotriene receptor antagonist add on therapy and step up inhaled Corticosteroid in partially controlled asthma: An open-labeled randomized controlled trial.

BACKGROUND: No studies are comparing the impact of the add-on leukotriene-receptor antagonist (LTRA) with a step-up dose of inhaled corticosteroids (ICS) in partly controlled asthma patients with asthma control test (ACT) score ˂ 23. OBJECTIVE: To study the effect of LTRA add-on therapy in comparison to a step-up to medium dose of ICS in partially controlled asthma. METHODS: An open-labeled randomized controlled trial was conducted in asthma subjects with partly controlled asthma who had been in regular receipt of low dose ICS. All subjects were assessed for asthma using ACT, daytime and nighttime symptoms, rate of relievers used, spirometry, and impulse oscillometry (IOS) at 3 and 6 months. Subjects were randomized to receive daily oral LTRA 10 mg or step-up medium dose of ICS. RESULTS: Between June 2020 and January 2021, 50 participants were enrolled, all patients completing the study. After treatment, mean ACT scores were increased to more than 23 indicating well-controlled asthma in both groups, control being sustained throughout the whole 6-month study period (P ˂ 0.001). Within each group, ACT scores were improved by a minimal clinical important difference (MCID) ≥ 3 points at 6 months, compared to baseline values. There were significant decreases in nighttime and daytime symptoms, and the numbers of rescue relievers used in 4 weeks in both groups compared to baseline (P ˂ 0.001). CONCLUSIONS: LTRA add-on therapy in partially controlled asthma patients is comparable with step-up to medium dose of ICS/LABA as regards asthma control.

The safety of pranlukast and montelukast during the first trimester of pregnancy: A prospective, two-centered cohort study in Japan.

For leukotriene receptor antagonists (LTRAs), especially pranlukast, safety data during pregnancy is limited. Therefore, we conducted a prospective, two-centered cohort study using data from teratogen information services in Japan to clarify the effects of LTRA exposure during pregnancy on maternal and fetal outcomes. Pregnant women who being counseled on drug use during pregnancy at two facilities were enrolled. The primary outcome of this study was major congenital anomalies. The incidence of major congenital anomalies in women exposed to montelukast or pranlukast during the first trimester of pregnancy was compared with that of controls. Logistic regression analysis was performed to analyze the effects of maternal LTRA use during the first trimester of pregnancy on major congenital anomalies. The outcomes of 231 pregnant women exposed to LTRAs (montelukast n = 122; pranlukast n = 106; both n = 3) and 212 live births were compared with those of controls. The rate of major congenital anomalies in the LTRA group was 1.9%. Multivariable logistic regression analysis revealed that LTRA exposure was not a risk factor for major congenital anomalies (adjusted odds ratio, 0.78; 95% confidence interval, 0.23-2.05; p = 0.653). In addition, no significant difference was detected in stillbirth, spontaneous abortion, preterm birth, and low birth weight between the two groups. The present study revealed that montelukast and pranlukast were not associated with the risk of major congenital anomalies. Our findings suggest that LTRAs could be safely employed for asthma therapy during pregnancy.

Cysteinyl Leukotriene Receptor Antagonists Associated With a Decreased Incidence of Cancer: A Retrospective Cohort Study.

Aim: Cysteinyl leukotrienes receptor antagonists (LTRAs) are promising chemoprevention options to target cysteinyl leukotriene signaling in cancer. However, only a number of randomized clinical trials (RCTs) or observational studies have been conducted to date; thus, the effect of LTRAs on patients is yet to be elucidated. Using insurance claim data, we aimed to evaluate whether LTRAs have cancer preventive effects by observing patients who took LTRAs. Method: Patients diagnosed with asthma, allergic rhinitis, chronic cough, and have no history of cancer were followed-up from 2005 to 2017. Cox proportional hazard regression analysis was conducted to estimate the hazard ratios (HRs) for cancer risk of LTRA users. Result: We followed-up (median: 5.6 years) 188,906 matched patients (94,453 LTRA users and 94,453 non-users). LTRA use was associated with a decreased risk of cancer (adjusted HR [aHR] = 0.85, 95% confidence interval [CI] = 0.83-0.87). The cancer risk showed a tendency to decrease rapidly when LTRAs were used in high dose (aHR = 0.56, 95% CI = 0.40-0.79) or for longer durations of more than 3 years (aHR = 0.68, 95% CI = 0.60-0.76) and 5 years (aHR = 0.33, 95% CI = 0.26-0.42). The greater preventive effects of LTRAs were also observed in patients with specific risk factors related to sex, age, smoking, and the presence of comorbidities. Conclusion: In this study, we found that LTRA use was associated with a decreased risk of cancer. The high dose and long duration of the use of LTRAs correlated with a lower cancer risk. Since LTRAs are not yet used for the prevention or treatment of cancer, our findings could be used for developing a new chemo-regimen or designing feasible RCTs.

Clinical and functional characteristics of OSA in children with comorbid asthma treated by leukotriene receptor antagonist: A descriptive study.

Background: Obstructive sleep apnea (OSA) is the most common form of respiratory disorders during sleep in children, especially those with severe asthma. However, optimal treatment of asthma might significantly improve OSA severity. Methods: It was a cohort study including children aged >5 years old and diagnosed with asthma according to GINA (Global Initiative for Asthma). The data related to age, gender, height, weight, body mass index (BMI), clinical symptoms and medical history of asthma, spirometry (FEV1: forced expiratory in 1 s), and exhaled nitric oxide (FENO) were recorded for analysis. Respiratory polygraphy (RPG) was done for each study subject to diagnose OSA and its severity. Results: Among 139 asthmatic children, 99 patients with OSA (71.2%) were included in the present study (9.3 ± 0.2 years): 58.6% with uncontrolled asthma and 32.3% with partial controlled asthma. The mean ACT (asthma control testing) score was 19.0 ± 3.4. The most frequent night-time symptoms were restless sleep (76.8%), snoring (61.6%), sweating (52.5%), and trouble breathing during sleep (48.5%). The common daytime symptoms were irritable status (46.5%) and abnormal behavior (30.3%). The mean AHI (apnea-hypopnea index) was 3.5 ± 4.0 events/h. There was a significant correlation between BMI and snoring index (R = 0.189 and P = 0.027), bronchial and nasal FENO with AHI (R = 0.046 and P < 0.001; R = 0.037 and P < 0.001; respectively). There was no significant correlation between asthma level, FEV1 and AHI. The severity of asthma and respiratory function were improved significantly after 3 months and 6 months of asthma treatment in combination with leukotriene receptor antagonist (LRA) treatment. The symptoms related to OSA were significantly improved after treatment with LRA. The severity of OSA was decreased significantly after 3 months and 6 months of treatment. Conclusion: The treatment of asthmatic children with comorbid OSA by LRA in combination with standard therapy for asthma could improve the control of asthma and the symptoms and severity of OSA.

The comparative effect of Leukotriene receptor antagonist add on therapy and step up inhaled Corticosteroid in partially controlled asthma: an open-labeled randomized controlled trial

Background No studies are comparing the impact of the add-on leukotriene-receptor antagonist (LTRA) with a step-up dose of inhaled corticosteroids (ICS) in partly controlled asthma patients with asthma control test (ACT) score ˂ 23.Objective To study the effect of LTRA add-on therapy in comparison to a step-up to medium dose of ICS in partially controlled asthma.Methods An open-labeled randomized controlled trial was conducted in asthma subjects with partly controlled asthma who had been in regular receipt of low dose ICS. All subjects were assessed for asthma using ACT, daytime and nighttime symptoms, rate of relievers used, spirometry, and impulse oscillometry (IOS) at 3 and 6 months. Subjects were randomized to receive daily oral LTRA 10 mg or step-up medium dose of ICS.Results Between June 2020 and January 2021, 50 participants were enrolled, all patients completing the study. After treatment, mean ACT scores were increased to more than 23 indicating well-controlled asthma in both groups, control being sustained throughout the whole 6-month study period (P ˂ 0.001). Within each group, ACT scores were improved by a minimal clinical important difference (MCID) ≥ 3 points at 6 months, compared to baseline values. There were significant decreases in nighttime and daytime symptoms, and the numbers of rescue relievers used in 4 weeks in both groups compared to baseline (P ˂ 0.001).Conclusions LTRA add-on therapy in partially controlled asthma patients is comparable with step-up to medium dose of ICS/LABA as regards asthma control (AU)

Leukotrienes Are Dispensable for Vaginal Neutrophil Recruitment as Part of the Immunopathological Response During Experimental Vulvovaginal Candidiasis.

Recruitment of polymorphonuclear neutrophils (PMNs) into the vaginal lumen is the hallmark of an acute immunopathologic inflammatory response during vulvovaginal candidiasis (VVC) caused by Candida albicans. Recurrent VVC (RVVC) remains a chronic health burden in affected women worldwide despite the use of antifungal therapy. Based on the role leukotrienes (LTs) play in promoting inflammation, leukotriene receptor antagonists (LTRAs) targeted for LTB4 (etalocib) or LTC4, LTD4, and LTE4 (zafirlukast or montelukast) have been shown to reduce inflammation of epithelial tissues. An open-label pilot study using long-term regimens of zafirlukast in women with RVVC indicated the potential for some relief from recurrent episodes. To investigate this clinical observation further, we evaluated the effects of LT antagonistic agents and LT deficiency on the immunopathogenic response in a mouse model of VVC. Results showed that mice given daily intraperitoneal injections of individual LTRAs, starting 2days prior to vaginal inoculation with C. albicans and continuing through 14days post-inoculation, had no measurable reduction in PMN migration. The LTRAs were also ineffective in reducing levels of the hallmark vaginal inflammatory markers (S100A8, IL-1ß) and tissue damage (LDH) associated with the immunopathogenic response. Finally, LT-deficient 5-lipoxygenase knockout mice showed comparable levels of vaginal fungal burden and PMN infiltration to wild-type mice following inoculation with a vaginal (ATCC 96113) or laboratory (SC5314) C. albicans isolate. These results indicate that despite some clinical evidence suggestive of off-target efficacy of LTRAs in RVVC, LTs and associated signaling pathways appear to be dispensable in the immunopathogenesis of VVC.

Leukotriene Receptor Antagonist Use and Dementia Risk in Patients With Asthma: A Retrospective Cohort Study.

BACKGROUND/AIM: Recent experimental studies have reported that leukotriene receptor antagonists (LTRAs) might protect against dementia. However, few clinical studies have examined this in humans. This study assessed whether the use of LTRAs can prevent the onset of dementia in humans. PATIENTS AND METHODS: A large population-based retrospective cohort study was conducted using a health insurance claims database in Japan, which included patients newly diagnosed with bronchial asthma between 2006 and 2015. Each of these patients that was LTRA user was matched with a randomly selected LTRA non-user according to age, sex, and bronchial asthma diagnostic year. RESULTS: There were 10,471 patients in both the LTRA user and the LTRA non-user group. Using Cox proportional hazards models, a significant reduction in the risk of developing dementia was observed in the LTRA user group compared to the non-user group (adjusted hazard ratio=0.42, 95% confidence interval=0.20-0.87, p=0.019). CONCLUSION: Our data suggest that the use of LTRAs may prevent the onset of dementia in asthmatic patients.

Leukotriene receptor antagonist use and cognitive decline in normal cognition, mild cognitive impairment, and Alzheimer's dementia.

BACKGROUND: Leukotriene receptor antagonists (LTRAs) alleviate Alzheimer's disease (AD) pathology and improve cognition in animal models; however, clinical evidence is limited. This study aimed to explore the associations between the use of LTRAs (montelukast or zafirlukast) and cognitive performance in people with normal cognition, mild cognitive impairment (MCI), or AD dementia. We hypothesized that LTRA use would be associated with better cognitive performance over time. METHODS: This longitudinal observational study used data from the National Alzheimer's Coordinating Center. Within groups of participants with normal cognition, MCI, or AD dementia, LTRA users were matched 1:3 to non-users using propensity score matching. Cognitive domains including immediate and delayed memory (Wechsler Memory Scale Revised-Logical Memory IA and IIA), psychomotor processing speed (Digit Symbol Substitution Test), and language (animal naming, vegetable naming, and Boston Naming Test) were compared between users and non-users in mixed-effects linear or Poisson regression models. RESULTS: In AD dementia, LTRA use was associated with a slower decline in psychomotor processing speed, as measured by the Digit Symbol Substitution Test (Β = 1.466 [0.253, 2.678] symbols/year, n = 442), and language, as measured by animal naming (Β = 0.541 [0.215, 0.866] animals/year, n = 566), vegetable naming (B = 0.309 [0.056, 0.561] vegetables/year, n = 565), and the Boston Naming Test (B = 0.529 [0.005, 1.053] items/year, n = 561). Effect sizes were small but persisted after controlling for a 10% false discovery rate. LTRA use was not associated with changes in memory performance in AD, nor was it associated with changes in cognitive performance in people with normal cognition or MCI. In a post hoc analysis, LTRA use was associated with a slower decline in clinical progression in MCI (B = -0.200 [-0.380, -0.019] points/year, n = 800) and AD dementia (B = -0.321 [-0.597, -0.046] points/year, n = 604) as measured by CDR Sum of Boxes. CONCLUSIONS: The use of LTRAs was associated with preserved function in non-amnestic cognitive domains in AD dementia. The role of leukotrienes and their receptors in cognitive decline warrants further investigation and the leukotriene pathway may represent a target for AD treatment.

The Addition of Montelukast for the Treatment of Chronic Idiopathic Urticaria.

Introduction Chronic urticaria (CU) is a common disorder that can significantly affect the quality of life. The goal of treatment is complete symptomatic relief. Conventional therapy, with antihistamines, is not always effective in all patients. Leukotrienes are believed to be involved in the pathogenesis of urticaria. Leukotriene receptor antagonists (LTRAs), such as montelukast, have been suggested as useful agents in patients with chronic idiopathic urticaria. Our objective is to document the efficacy of montelukast in our patients. Materials and methods Patients who received montelukast were identified from clinic letters. Data including clinical features were collected and analyzed. The main endpoint was adequate disease control. Results A total of nine patients who met the inclusion criteria were included in this study. Four patients reported having a good response to montelukast and three patients reported full control of the disease. Conclusion These findings suggest that leukotriene antagonists, such as montelukast, are effective as an add-on therapy to anti-histamines and their use in histamine resistant patients is justifiable.

Management of allergic rhinitis with leukotriene receptor antagonists versus selective H1-antihistamines: a meta-analysis of current evidence.

BACKGROUND: Inconsistencies remain regarding the effectiveness and safety of leukotriene receptor antagonists (LTRAs) and selective H1-antihistamines (SAHs) for allergic rhinitis (AR). A meta-analysis of randomized controlled trials (RCTs) was conducted to compare the medications. METHODS: Relevant head-to-head comparative RCTs were retrieved by searching the PubMed, Embase, and Cochrane's Library databases from inception to April 20, 2020. A random-effects model was applied to pool the results. Subgroup analyses were performed for seasonal and perennial AR. RESULTS: Fourteen RCTs comprising 4458 patients were included. LTRAs were inferior to SAHs in terms of the daytime nasal symptoms score (mean difference [MD]: 0.05, 95% confidence interval [CI] 0.02 to 0.08, p = 0.003, I2 = 89%) and daytime eye symptoms score (MD: 0.05, 95% CI 0.01 to 0.08, p = 0.009, I2 = 89%), but were superior in terms of the nighttime symptoms score (MD: - 0.04, 95% CI - 0.06 to - 0.02, p < 0.001, I2 = 85%). The effects of the two treatments on the composite symptom score (MD: 0.02, 95% CI - 0.02 to 0.05, p = 0.30, I2 = 91%) and rhinoconjunctivitis quality-of-life questionnaire (RQLQ) (MD: 0.01, 95% CI - 0.05 to 0.07, p = 0.71, I2 = 99%) were similar. Incidences of adverse events were comparable (odds ratio [OR]: 0.97, 95% CI 0.75 to 1.25, p = 0.98, I2 = 0%). These results were mainly obtained from studies on seasonal AR. No significant publication bias was detected. CONCLUSIONS: Although both treatments are safe and effective in improving the quality of life (QoL) in AR patients, LTRAs are more effective in improving nighttime symptoms but less effective in improving daytime nasal symptoms compared to SAHs.