Pharmacokinetics of montelukast in asthmatic patients 6 to 24 months old

Updates in the treatment of asthma in pediatrics: A review for pharmacists

PURPOSE

The purpose of this review is to summarize the management of asthma in children and to highlight different guideline-based approaches. This review also discusses literature regarding the use of corticosteroids, both inhaled and systemic, as well as biologic agents, in asthma management.

SUMMARY

Asthma is a common chronic respiratory condition in the pediatric population and has evolved into a highly patient-specific disease. Of the 2 main asthma guidelines, one developed by the National Asthma Education and Prevention Program was recently published as a focused update in 2020. The other, from the Global Initiative for Asthma, focuses on a global strategy for management and prevention, with the most recent update in 2023. Both reports discuss diagnosis, assessment, and treatment of asthma in adults and children. Treatment is designed as a stepwise approach in both reports, although there are key differences. This article focuses on gaps in these guidelines, including the use of bronchodilators and inhaled corticosteroids with single maintenance and reliever therapy and long-acting muscarinic antagonists in children. It also reviews treatment in children under 5 years of age, although recommendations are limited due to a lack of evidence in this age group. Finally, this review discusses considerations for emerging treatments, including biologics, for patients who are difficult to treat.

CONCLUSION

New treatment strategies and agents have emerged in the treatment of pediatric asthma. Pharmacists play a key role in providing education about, dispensing, and recommending the newest evidence-based treatment options for children.

Performance Evaluation of Montelukast Pediatric Formulations: Part II - a PBPK Modelling Approach

This study aimed to build a physiologically based pharmacokinetic (PBPK) model coupled with age-appropriate in vitro dissolution data to describe drug performance in adults and pediatric patients. Montelukast sodium was chosen as a model drug. Two case studies were investigated: case study 1 focused on the description of formulation performance from adults to children; case study 2 focused on the description of the impact of medicine co-administration with vehicles on drug exposure in infants. The PBPK model for adults and pediatric patients was developed in Simcyp^® v18.2 informed by age-appropriate in vitro dissolution results obtained in a previous study. Oral administration of montelukast was simulated with the ADAM™ model. For case study 1, the developed PBPK model accurately described montelukast exposure in adults and children populations after the administration of montelukast chewable tablets. Two-stage dissolution testing in simulated fasted gastric to intestinal conditions resulted in the best description of in vivo drug performance in adults and children. For case study 2, a good description of in vivo drug performance in infants after medicine co-administration with vehicles was achieved by incorporating in vitro drug dissolution (under simulated fasted gastric to fed intestinal conditions) into a fed state PBPK model with consideration of the in vivo dosing conditions (mixing of formulation with applesauce or formula). The case studies presented demonstrate how a PBPK absorption modelling strategy can facilitate the description of drug performance in the pediatric population to support decision-making and biopharmaceutics understanding during pediatric drug development.

Performance Evaluation of Montelukast Pediatric Formulations: Part I-Age-Related In Vitro Conditions

This study aimed to explore the potential of biopharmaceutics in vitro tools to predict drug product performance in the pediatric population. Biorelevant dissolution set-ups were used to predict how age and medicine administration practices affect the in vitro dissolution of oral formulations of a poorly water-soluble compound, montelukast. Biorelevant age-appropriate dissolution studies of Singulair^® (granules and chewable tablets) were conducted with the µDISS profiler™, USP 4 apparatus, USP 2 apparatus, and mini-paddle apparatus. Biorelevant simulating fluids representative of adult and pediatric conditions were used in the dissolution studies. The biorelevant dissolution conditions were appropriately selected (i.e. volumes, transit times, etc.) to mimic the gastrointestinal conditions of each of the subpopulations tested. Partial least squares regression (PLS-R) was performed to understand the impact of in vitro variables on the dissolution of montelukast. Montelukast dissolution was significantly affected by the in vitro hydrodynamics used to perform the dissolution tests (µDISS profiler™: positive effect); choice of simulation of gastric (negative effect) and/or intestinal conditions (positive effect) of the gastrointestinal tract; and simulation of prandial state (fasted state: negative effect, fed state: positive effect). Age-related biorelevant dissolution of Singulair^® granules predicted the in vivo effect of the co-administration of the formulation with applesauce and formula in infants. This study demonstrates that age-appropriate biorelevant dissolution testing can be a valuable tool for the assessment of drug performance in the pediatric population.

Ontogeny of Drug-Metabolizing Enzymes

Almost 50% of prescription drugs lack age-appropriate dosing guidelines and therefore are used "off-label." Only ~10% drugs prescribed to neonates and infants have been studied for safety or efficacy. Immaturity of drug metabolism in children is often associated with drug toxicity. This chapter summarizes data on the ontogeny of major human metabolizing enzymes involved in oxidation, reduction, hydrolysis, and conjugation of drugs. The ontogeny data of individual drug-metabolizing enzymes are important for accurate prediction of drug pharmacokinetics and toxicity in children. This information is critical for designing clinical studies to appropriately test pharmacological hypotheses and develop safer pediatric drugs, and to replace the long-standing practice of body weight- or surface area-normalized drug dosing. The application of ontogeny data in physiologically based pharmacokinetic model and regulatory submission are discussed.

In Vivo Predictive Dissolution Testing of Montelukast Sodium Formulations Administered with Drinks and Soft Foods to Infants

In vitro dissolution testing conditions that reflect and predict in vivo drug product performance are advantageous, especially for the development of paediatric medicines, as clinical testing in this population is hindered by ethical and technical considerations. The aim of this study was to develop an in vivo predictive dissolution test in order to investigate the impact of medicine co-administration with soft food and drinks on the dissolution performance of a poorly soluble compound. Relevant in vitro dissolution conditions simulating the in vivo gastrointestinal environment of infants were used to establish in vitro-in vivo relationships with corresponding in vivo data. Dissolution studies of montelukast formulations were conducted with mini-paddle apparatus on a two-stage approach: infant fasted-state simulated gastric fluid (Pi-FaSSGF; for 1 h) followed by either infant fasted-state or infant fed-state simulated intestinal fluid (FaSSIF-V2 or Pi-FeSSIF, respectively; for 3 h). The dosing scenarios tested reflected in vivo paediatric administration practices: (i.) direct administration of formulation; (ii.) formulation co-administered with vehicles (formula, milk or applesauce). Drug dissolution was significantly affected by co-administration of the formulation with vehicles compared with after direct administration of the formulation. Montelukast dissolution from the granules was significantly higher under fed-state simulated intestinal conditions in comparison with the fasted state and was predictive of the in vivo performance when the granules are co-administered with milk. This study supports the potential utility of the in vitro biorelevant dissolution approach proposed to predict in vivo formulation performance after co-administration with vehicles, in the paediatric population.

Developmental Pharmacogenetics of SLCO2B1 on Montelukast Pharmacokinetics in Chinese Children

Background

Montelukast, a potent oral selective leukotriene-receptor antagonist, inhibits the action of cysteinyl-leukotriene in patients with asthma. Although pharmacokinetic studies of montelukast have been reported in Caucasian adults and children, and showed large inter-individual variability on pharmacokinetics, none of these studies has been explored in Chinese children. Given the potential inter-ethnic difference, the purpose of the present study was to evaluate the effects of developmental factors and pharmacogenetics of CYP2C8 and SLCO2B1 on montelukast clearance in Chinese pediatric patients.

Methods

After the administration of montelukast, blood samples were collected from children and plasma concentrations were determined using an adapted micro high-performance liquid chromatography coupled with the fluorescence detection (HPLC-FLD) method. A previously published pharmacokinetic model was validated using the opportunistic pharmacokinetic samples, and individual patient’s clearance was calculated using the validated model. Population pharmacokinetic analysis was performed using a nonlinear mixed-effects model approach (NONMEM V 7.2.0) and variants of CYP2C8 and SLCO2B1 were genotyped.

Results

Fifty patients (age range: 0.7–10.0 years) with asthma were enrolled in this study. The clearance of montelukast was significantly higher in children with the SLCO2B1 c.935GA and c.935AA genotypes compared with that of children with the SLCO2B1 c.935GG genotype (0.94 ± 0.26 versus 0.77 ± 0.21, p = 0.020). The patient’s weight was also found to be significantly corrected with montelukast clearance (p <0.0001).

Conclusion

The developmental pharmacology of montelukast in Chinese children was evaluated. Weight and SLCO2B1 genotype were found to have independent significant impacts on the clearance of montelukast.

Pediatric acute asthma exacerbations: Evaluation and management from emergency department to intensive care unit

OBJECTIVE

The goal of this report is to review available modalities for assessing and managing acute asthma exacerbations in pediatric patients, including some that are not included in current expert panel guidelines. While it is not our purpose to provide a comprehensive review of the National Asthma Education and Prevention Program (NAEPP) guidelines, we review NAEPP-recommended treatments to provide the full range of treatments available for managing exacerbations with an emphasis on the continuum of care between the ER and ICU.

DATA SOURCES

We searched PubMed using the following search terms in different combinations: asthma, children, pediatric, exacerbation, epidemiology, pathophysiology, guidelines, treatment, management, oxygen, albuterol, β2-agonist, anticholinergic, theophylline, corticosteroid, magnesium, heliox, BiPAP, ventilation, mechanical ventilation, non-invasive mechanical ventilation and respiratory failure. We attempted to weigh the evidence using the hierarchy in which meta-analyses of randomized controlled trials (RCTs) provide the strongest evidence, followed by individual RCTs, followed by observational studies. We also reviewed the NAEPP and Global Initiative for Asthma expert panel guidelines.

RESULTS AND CONCLUSIONS

Asthma is the most common chronic disease of childhood, and acute exacerbations are a significant burden to patients and to public health. Optimal assessment and management of exacerbations, including appropriate escalation of interventions, are essential to minimize morbidity and prevent mortality. While inhaled albuterol and systemic corticosteroids are the mainstay of exacerbation management, escalation may include interventions discussed in this review.

Montelukast medicines of today and tomorrow: from molecular pharmaceutics to technological formulations

Montelukast sodium is a leukotriene antagonist of growing interest as an alternative therapy for asthma across different age groups due to its bronchoprotective, anti-inflammatory and anti-allergic properties. Currently, montelukast is commercialized only in oral solid dosage forms, which are the favorite of adult patients but may pose challenges in administration to children of young age or patients suffering from dysphagia. This review presents a comprehensive revision of scientific reports and patents on emerging strategies for the delivery of montelukast. A common ground to these reports is the pursue of an enhanced montelukast performance, by increasing its bioavailability and physico-chemical stability. A wide variety of strategies can be found, from the formation of supramolecular adducts with cyclodextrins to encapsulation in nanoparticles and liposomes. The new dosage forms for montelukast are designed for non-enteric absorption, some for absorption in the oral cavity and another two being for local action in the nasal mucosa or in the pulmonary epithelium. The review describes the emerging delivery strategies to circumvent the current limitations to the use of montelukast that are expected to ultimately lead to the development of more patient-compliant dosage forms.

Bioequivalence of two formulations of montelukast sodium 4 mg oral granules in healthy adults

Montelukast is an effective and well-tolerated treatment for the prophylaxis and chronic treatment of asthma, acute prevention of exercise-induced bronchoconstriction and symptomatic relief of seasonal allergic rhinitis and perennial allergic rhinitis. The aim of the study was to compare bioavailability, and characterise the pharmacokinetic profile and safety of Sandoz generic montelukast 4 mg oral granules relative to Singulair^® mini (Merck, Sharp & Dohme). An open-label, randomised, single-dose, two-treatment, two-period, two-sequence, two-way crossover bioequivalence study was conducted in healthy male volunteers aged 18–55 years, under fasting conditions. The duration of the clinical part of the trial was ≈ 11 days. Montelukast levels in plasma were quantified using a validated liquid chromatography tandem mass spectrometry method, and pharmacokinetic parameters calculated from the drug concentration–time profile using a non-compartmental model. A total of 40 subjects completed both study periods. The ratio test/reference of geometric least squares means was calculated for both formulations of montelukast for the In-transformed pharmacokinetic parameters; the 90% confidence intervals (CIs) were within the pre-defined limits of 80.00–125.00%: 92.2% (90% CI: 87.42–97.30%) for C_max, 98.1% (90% CI: 94.49–101.81%) for AUC_0–t and 97.6% (90% CI: 94.14–101.27%) for AUC_0–∞. Two study subjects each reported one mild adverse event: dyspepsia (possibly related to study medication) and throat pain (not considered related to study medication). Sandoz montelukast 4 mg oral granules are bioequivalent to Singulair^® 4 mg mini oral granules, with a similar safety profile. This suggests that these two preparations can be considered interchangeable in clinical practice.

Montelukast-loaded nanostructured lipid carriers: part I oral bioavailability improvement

The purpose of the study was to formulate montelukast-loaded nanostructured lipid carrier (MNLC) to improve its systemic bioavailability, avoid hepatic metabolism and reduce hepatic cellular toxicity due to metabolites. MNLC was prepared using melt-emulsification-homogenization method. Preformulation study was carried out to evaluate drug-excipient compatibility. MNLCs were prepared using spatially different solid and liquid lipid triglycerides. CAE (DL-Pyrrolidonecarboxylic acid salt of L-cocyl arginine ethyl ester), a cationic, biodegradable, biocompatible surfactant was used to stabilize the system. MNLCs were characterized by FTIR, XRPD and DSC to evaluate physicochemical properties. MNLCs having a particle size of 181.4 ± 6.5 nm with encapsulation efficiency of 96.13 ± 0.98% were prepared. FTIR findings demonstrated no interaction between the drug and excipients of the formulation which could lead to asymmetric vibrations. DSC and XRPD study confirmed stable amorphous form of the montelukast in lipid matrix. In vitro release study revealed sustained release over a period of 24 h. In vivo single dose oral pharmacokinetic study demonstrated 143-fold improvement in bioavailability as compared to montelukast-aqueous solution. Thus, the result of this study implies that developed MNLC formulation be suitable to sustain the drug release with improvement in the bioavailability.

Effect of different monotherapies on serum nitric oxide and pulmonary functions in children with mild persistent asthma

INTRODUCTION

Common medications used to treat mild persistent asthma are glucocorticoids, leukotriene receptor antagonists and theophylline. The aim of the study was to evaluate monotherapy with either inhaled steroids, oral leukotriene receptor antagonist or theophylline in Egyptian children with mild persistent asthma by determining their clinical, laboratory and spirometric responses to treatment.

MATERIAL AND METHODS

Thirty-nine mild asthmatic children between 8 and 13 years of age were included in the study. Patients were classified according to therapy received into four groups: oral leukotriene receptor antagonist (montelukast), inhaled corticosteroid (fluticasone propionate), sustained-release (SR) theophylline, and no treatment. Pulmonary function testing was performed at the start of therapy and 8 weeks later using spirometry. Eosinophil count and serum nitric oxide were estimated in the blood. Minitab statistical package was used for analysis of data.

RESULTS

Follow-up after 8 weeks revealed significant improvement in FEV1% in groups 1 (p < 0.01) and 3 (p < 0.05), significant improvement in PEFR in groups 1 (p < 0.05) and 2 (p < 0.01), significant decline in serum NO levels in groups 1 (p < 0.05) and 2 (p < 0.05), as well as significant improvement in eosinophil count in groups 1, 2 and 3 (p < 0.01, < 0.001, < 0.01 respectively). There was a statistically significant positive correlation between the decline in serum NO and the decline in blood eosinophil % in group 2 (p < 0.05).

CONCLUSIONS

Inhaled corticosteroids and montelukast have a significant role in controlling the pulmonary functions and the inflammatory process in children with mild persistent asthma, although inhaled corticosteroids seem to yield a better response. Children with mild persistent asthma should receive a controller medication, and SR theophylline may be a good cost-benefit alternative for low socio-economic groups of patients.

Montelukast in the treatment of asthma and beyond

Asthma is a chronic inflammatory disease affecting over 300 million people worldwide. The common association with allergic rhinitis and the presence of proinflammatory cells and mediators in the circulation of patients qualify asthma as a systemic disease. This characteristic and the fact that the gold-standard therapy for persistent asthma, inhaled corticosteroids, cannot suppress all components of airway inflammation and fail to adequately penetrate into the small airways, warrant the quest for effective systemic anti-asthma therapies. This review describes the most important controlled studies of montelukast, a once-daily leukotriene receptor antagonist, in asthma and allergic rhinitis in both adults and children. Montelukast is a systemically active drug with a targeted, dual mechanism of action, acting both as a bronchodilator and anti-inflammatory. In patients of all ages, montelukast has shown a favorable safety profile and was well-tolerated. Both as monotherapy or in combination with inhaled corticosteroids, montelukast produced clinically relevant improvements in asthma-related parameters, including symptoms, lung function parameters, quality of life and the number of asthma exacerbations. Furthermore, bronchoprotective effects have been reported both against specific and nonspecific bronchoactive stimuli. Similarly, in patients with allergic rhinitis, montelukast produced substantial improvements in symptoms and quality of life. Long-term studies aimed to determine its effects on airway remodeling are still lacking.

Montelukast in the treatment of asthma as a systemic disease

Asthma affects 300 million people worldwide. The common association of asthma with allergic rhinitis and the presence of proinflammatory mediators in the circulation of patients provide strong evidence for the need to treat asthma as a systemic disease. The leukotriene receptor antagonist montelukast is a disease-specific oral medication that has dual effects on airway smooth muscle cells and inflammatory processes. This review describes recent randomized, controlled studies of montelukast in asthma and allergic rhinitis in adults and children as young as 3 months old. Montelukast treatment consistently produced significant reductions in asthma exacerbations. While many patients may benefit from montelukast as monotheray, combination treatment for chronic asthma with inhaled corticosteroids is advocated as being rational. Significant improvements in symptoms and quality of life were observed in allergic rhinitis patients. Montelukast is well tolerated in patients of all ages. Long-term studies are underway to determine its effects on airway remodeling.

Bioequivalence of the 4-mg Oral Granules and Chewable Tablet Formulations of Montelukast

Purpose

The primary objective of the studies was to demonstrate bioequivalence between the oral granules formulation and chewable tablet of montelukast in the fasted state. Effect of food on the pharmacokinetics of the oral granules was also evaluated.

Methods

The Formulation Biocomparison Study (Study 1) and the Final Market Image Study (Study 2) each used an open-label, randomized, 3-period crossover design where healthy adult subjects (N = 24 and 30, respectively) received montelukast as a single 4-mg dose of the oral granules formulation and a 4-mg chewable tablet fasted, and a single 4-mg dose of the oral granules formulation with food (on 2 teaspoons of applesauce [Study 1] or after consumption of a high-fat breakfast [Study 2]). The formulations were to be considered bioequivalent if the 90% confidence intervals (CIs) for geometric mean ratios (GMRs) (oral granules/chewable tablet) for the AUC_0-∞ and C_max of montelukast were within the prespecified comparability bounds of (0.80, 1.25). For the food-effect assessment in Study 1, comparability bounds were prespecified as (0.50, 2.00) only for the 90% CI of the GMR (oral granules fed/oral granules fasted) for the AUC_0-∞ of montelukast; the 90% CI of the GMR for the C_max of montelukast, however, also was computed. In Study 2, 90% CIs of the GMRs (oral granules fed/oral granules fasted) for the AUC_0-∞ and C_max of montelukast were computed; comparability bounds were not prespecified.

Results

Comparing the exposure of the formulations, the 90% CIs of the GMRs for AUC_0-∞ and C_max were within the prespecified bound of (0.80, 1.25). For AUC_0-∞, the GMRs (90% CI) for Study 1 and Study 2 were 1.01 (0.92, 1.11) and 0.95 (0.91, 0.99), respectively. For C_max, respective values were 0.99 (0.86, 1.13) and 0.92 (0.84, 1.01). When the oral granules formulation was administered with food, 90% CIs of the GMRs for both AUC_0-∞ and C_max in both studies were contained within the interval of (0.50, 2.00).

Conclusions

The 4-mg oral granules and 4-mg chewable tablet formulations of montelukast administered in the fasted state are bioequivalent. Single 4-mg doses of the oral granules formulation and the chewable tablet of montelukast are generally well tolerated.

Montelukast in the treatment of duodenal eosinophilia in children with dyspepsia: effect on eosinophil density and activation in relation to pharmacokinetics

Background

We have previously demonstrated the clinical efficacy of montelukast in a randomized double-blind controlled cross-over trial in patients with dyspepsia in association with duodenal eosinophilia. The mechanism of this clinical response is unknown but could involve a decrease in eosinophil density or activation.

Methods

Twenty-four dyspeptic patients 8–17 years of age underwent initial blood sampling and endoscopy with biopsy. Eighteen of these patients had elevated duodenal eosinophil density and underwent repeat blood sampling and endoscopy following 21 days of therapy with montelukast (10 mg/day). The following were determined: global clinical response on a 5-point Lickert-type scale, eosinophil density utilizing H & E staining, eosinophil activation determined by degranulation indices on electron microscopy, and serum cytokine concentrations. On day 21, pharmacokinetics and duodenal mucosal drug concentrations were determined.

Results

Eighty-three percent of the patients had a positive clinical response to montelukast with regard to relief of pain with 50% having a complete or nearly complete clinical response. The response was unrelated to systemic drug exposure or to mucosal drug concentration. Other than a mild decrease in eosinophil density in the second portion of the duodenum, there were no significant changes in eosinophil density, eosinophil activation, or serum cytokine concentrations following treatment with montelukast. Pre-treatment TNF-α concentration was negatively correlated with clinical response.

Conclusion

The short-term clinical response to montelukast does not appear to result from changes in eosinophil density or activation. Whether the effect is mediated through specific mediators or non-inflammatory cells such as enteric nerves remains to be determined.

Trial Registration

ClinicalTrials.gov; NCT00148603

Fluticasone or montelukast for preschool children with asthma-like symptoms: Randomized controlled trial

RATIONALE

Beneficial effects of anti-inflammatory therapy such as fluticasone propionate (FP) and montelukast (Mk) have been demonstrated in preschool children with asthma. However, comparative studies are lacking in this age group. Therefore, we conducted a study to evaluate and compare the effect of FP and Mk in preschool children with asthma-like symptoms.

METHODS

In this multicenter, randomized, placebo-controlled, double-blind, double-dummy trial, children aged 2-6 years with asthma-like symptoms were included. In total, 63 children were randomly allocated to receive FP (25), Mk (18) or placebo (20) for 3 months. The primary outcome was the daily symptom score (wheeze, cough, shortness of breath) as recorded by caregivers in a symptom diary card. Secondary endpoints were rescue medication free days, blood eosinophils and lung function (interrupter technique and forced oscillation technique (FOT)).

RESULTS

During the 3 months study period, symptoms improved in all 3 groups, with a statistically significant difference between FP and placebo in favor of the FP group (p=0.021). A significant reduction in circulating eosinophils after 3 months of treatment was found in the Mk group only (p=0.008), which was significantly different from the change found in the placebo group (p=0.045). With the exception of frequency dependence (measured by FOT), which showed a difference between FP and Mk after 3 months of treatment in favor of the FP group (p=0.048), no differences in lung function within or between groups were found.

CONCLUSIONS

In spite of a lack of power, our results suggest that FP has a beneficial effect on symptoms and Mk on blood eosinophil level as compared to placebo. Except for a difference in one lung function parameter after 3 months between FP and Mk in favor of the FP group, this study revealed no differences between FP and Mk.

Expression of enzymes and receptors of the leukotriene pathway in human neuroblastoma promotes tumor survival and provides a target for therapy

The metabolism of arachidonic acid by the cyclooxygenase (COX) or lipoxygenase (LO) pathways generates eicosanoids that have been implicated in the pathogenesis of a variety of human diseases, including cancer. In this study, we examined the expression and significance of components within the 5-LO pathway in human neuroblastoma, an embryonal tumor of the sympathetic nervous system. High expression of 5-LO, 5-LO-activating protein (FLAP), leukotriene A(4) hydrolase, leukotriene C(4) synthase, and leukotriene receptors was detected in a majority of primary neuroblastoma tumors and all cell lines investigated. Expression of 5-LO and FLAP was evident in tumor cells but not in nonmalignant adrenal medulla where neuroblastomas typically arise. Moreover, neuroblastoma cells produce leukotrienes, and stimulation of neuroblastoma cells with leukotrienes increased neuroblastoma cell viability. Inhibitors of 5-LO (AA-861), FLAP (MK-886), or the leukotriene receptor antagonist montelukast inhibited neuroblastoma cell growth by induction of G(1)-cell cycle arrest and apoptosis. Similarly, specific 5-LO and leukotriene receptor silencing by small interfering RNA decreased neuroblastoma cell growth. These findings provide new insights into the pathobiology of neuroblastoma, and the use of leukotriene pathway inhibitors as a novel adjuvant therapy for children with neuroblastoma warrants further consideration.

Pharmacokinetics and safety of montelukast oral granules in children 1 to 3 months of age with bronchiolitis

The single-dose pharmacokinetics of montelukast 4-mg oral granules and tolerability of daily administration of 2 different doses of montelukast (4 mg and 8 mg given once daily for 7 days) versus placebo were evaluated in 12 infants 1 to 3 months of age with bronchiolitis or a history of bronchiolitis and asthma-like symptoms. The population area under the concentration-time curve estimate after a single 4-mg dose of montelukast was 13 195.7 +/- 2309.8 (standard error) ng.hr/mL, 3.6 times higher than historical values in infants 3 to 24 months of age. Six patients had 10 total clinical adverse experiences; none was considered serious or drug related. Three patients had transient drug-related increases in aspartate aminotransferase (montelukast 8 mg [n = 2]; placebo [n = 1]). Despite increased systemic exposure after administration of a single dose of montelukast 4-mg oral granules in infants 1 to 3 months of age compared with that in pediatric patients 3 to 24 months of age, administration of montelukast at 4 and 8 mg once daily for 7 days in 1- to 3-month-old infants was generally well tolerated.

Asthma

Asthma has been recognized as a disease since the earliest times. In the Corpus Hippocraticum, Hippocrates used the term “ασθμα” to indicate any form of breathing difficulty manifesting itself by panting. Aretaeus of Cappadocia, a well-known Greek physician (second century A.D.), is credited with providing the first detailed description of an asthma attack [13], and to Celsus it was a disease with wheezing and noisy, violent breathing. In the history of Rome, we find many members of the Julio-Claudian family affected with probable atopic respiratory disorders: Caesar Augustus suffered from bronchoconstriction, seasonal rhinitis as well as a highly pruritic skin disease. Claudius suffered from rhinoconjunctivitis and Britannicus was allergic to horse dander [529]. Maimonides (1136–1204) warned that to neglect treatment of asthma could prove fatal, whereas until the 19th century, European scholars defined it as “nervous asthma,” a term that was given to mean a defect of conductivity of the ninth pair of cranial nerves.

Pharmacokinetics and safety of montelukast in children aged 3 to 6 months

The single-dose population estimate of the area under the concentration-time curve (AUC(pop)) from time zero to infinity (AUC(0-infinity)), maximum plasma concentration (C(max)), and time to C(max) (t(max)) of montelukast 4-mg oral granules were investigated in infants aged 3 to 6 months. Montelukast concentrations were quantitated after a single 4-mg dose of montelukast oral granules. Pharmacokinetic parameters were determined using a population-based approach with a nonlinear mixed-effect, 1-compartment model with first-order absorption and elimination. Ninety-five percent confidence intervals for the AUC(pop) ratio (3 to 6 months/6 to 24 months) were determined. Safety and tolerability were assessed. Montelukast 4-mg oral granules in children 3 to 6 months of age yielded systemic exposure (AUC(pop) = 3644.3 +/- 481.5 ng x h/mL) similar to that observed in children aged 6 to 24 months (3226.6 +/- 250.0 ng x h/mL). Systemic exposure after a 4-mg dose of montelukast as oral granules is similar in children aged 3 to 6 months and 6 to 24 months.

Montelukast in pediatric asthma management

Leukotriene modifiers (receptor antagonist and biosynthesis inhibitor) represent the first mediator specific therapeutic option for asthma. Montelukast, a leukotriene receptor antagonist is the only such agent approved for use in pediatric patients. Montelukast modifies action of leukotrienes, which are the most potent bronchoconstrictors, by blocking Cysteinyl leukotriene receptors. Systemic drug like mountelukast can reach lower airways and improves the peripheral functions which play a crucial role in the evolution of asthma. Review of existing literature showed that montelukast compared to placebo has proven clinical efficacy in better control of day time asthma symptoms, percentage of symptom free days, need for rescue drugs and improvement in FEV 1. Studies also demonstrated improvement in airway inflammation as indicated by reduction in fractional exhaled nitric oxide, a marker of inflammation. Studies comparing low dose inhaled corticosteroids (ICS) with montelukast are limited in children and conclude that it is not superior to ICS. For moderate to severe persistent asthma, montelukast has been compared with long acting beta agonists (LABA) as an add-on therapy to ICS, montelukast was less efficacious and less cost-effective. It has beneficial effects in exercise induced asthma and aspirin-sensitive asthma. Montelukast has onset of action within one hour. Patient satisfaction and compliance was better with montelukast than inhaled anti-inflammatory agents due to oral, once a day administration. The recommended doses of montelukast in asthma are- children 1-5 years: 4 mg chewable tablet, children 6-14 years: 5mg chewable tablet,

ADULTS

10mg tablet; administered once daily. The drug is well tolerated. Based on the presently available data montelukast may be an alternative treatment for mild persistent asthma as monotherapy where ICS cannot be administered. It is also an alternative to LABA as an add-on therapy to ICS for moderate to severe persistent asthma. The other indications for use of montelukast include: allergic rhinitis, exercise induced bronchoconstriction and aspirin-induced asthma.

Montelukast administered in the morning or evening to prevent exercise-induced bronchoconstriction in children

Montelukast is recommended to be taken in the evening. The effectiveness of this drug to prevent exercise-induced bronchoconstriction (EIB) in children was already evaluated. However, there is no information to determine if this effectiveness could vary depending on dosage time. Children (n = 24) with a documented history of EIB performed an exercise challenge test before starting montelukast treatment. Twelve children were randomly allocated to receive the drug in the morning for 2 weeks, and another 12 to receive it in the evening. After this treatment period and after a week of washout, the children were crossed over. An exercise test was repeated after the first and second periods of treatment. Values obtained after morning or evening dosage were compared with pretreatment values for the whole group of children. There was a significant effect of montelukast for protecting against EIB, measured both as percent of maximum fall in forced expired volume in 1 sec (FEV1) (18.9 +/- 9.7, morning, 18.7 +/- 11.3, evening, vs. 27.5 +/- 9.8, pretreatment; P < 0.05) or as area under the curve (156.4 +/- 102.0, morning, 145.4 +/- 130.6, evening, vs. 294.3 +/- 156.5, pretreatment; P < 0.005). There were no statistical differences between taking the drug in the morning or evening. In conclusion, montelukast, taken for 2 weeks, is equally effective in exercise-induced bronchoconstriction when dosing either in the morning or in the evening.

CysLT1 leukotriene receptor antagonists inhibit the effects of nucleotides acting at P2Y receptors

Montelukast and pranlukast are orally active leukotriene receptor antagonists selective for the CysLT1 receptor. Conversely, the hP2Y(1,2,4,6,11,12,13,14) receptors represent a large family of GPCRs responding to either adenine or uracil nucleotides, or to sugar-nucleotides. Montelukast and pranlukast were found to inhibit nucleotide-induced calcium mobilization in a human monocyte-macrophage like cell line, DMSO-differentiated U937 (dU937). Montelukast and pranlukast inhibited the effects of UTP with IC50 values of 7.7 and 4.3 microM, respectively, and inhibited the effects of UDP with IC50 values of 4.5 and 1.6 microM, respectively, in an insurmountable manner. Furthermore, ligand binding studies using [3H]LTD4 excluded the possibility of orthosteric nucleotide binding to the CysLT1 receptor. dU937 cells were shown to express P2Y2, P2Y4, P2Y6, P2Y11, P2Y13 and P2Y14 receptors. Therefore, these antagonists were studied functionally in a heterologous expression system for the human P2Y receptors. In 1321N1 astrocytoma cells stably expressing human P2Y(1,2,4,6) receptors, CysLT1 antagonists inhibited both the P2Y agonist-induced activation of phospholipase C and intracellular Ca2+ mobilization. IC50 values at P2Y1 and P2Y6 receptors were <1 microM. In control astrocytoma cells expressing an endogenous M3 muscarinic receptor, 10 microM montelukast had no effect on the carbachol-induced rise in intracellular Ca2+. These data demonstrated that CysLT1 receptor antagonists interact functionally with signaling pathways of P2Y receptors, and this should foster the study of possible implications for the clinical use of these compounds in asthma or in other inflammatory conditions.

Childhood asthma. Balancing efficacy and adherence for optimum management

In the United States, asthma is the most common cause of school absences due to chronic illness, and its incidence in the pediatric population is increasing. Although most cases of childhood asthma can be controlled with recently available medications, there is often a gap between the goal of optimal control and the actual persistence of symptoms. In this article, Dr Sveum explores one approach to the most advantageous management of childhood asthma-an approach that weighs the advantage of a higher rate of medication adherence in practice against greater medication efficacy in clinical trials.

Safety, tolerability, and exploratory efficacy of montelukast in 6- to 24-month-old patients with asthma

OBJECTIVE

The purpose of this study was to determine the safety and tolerability profile of montelukast 4-mg oral granules compared with placebo in children aged 6-24 months with asthma.

METHODS

This was a randomized, double-blind, placebo-controlled, parallel-group study. Children 6-24 months of age at first visit with a history of at least three episodes of physician-diagnosed asthma or 'asthma-like' symptoms and in need of controller therapy were randomized to either montelukast 4-mg oral granules or placebo once daily in the evening for 6 weeks. The primary variables were the frequency of clinical and laboratory adverse experiences. The exploratory efficacy endpoints included days without beta-agonist use, beta-agonist use per day, unscheduled physician or hospital visits for asthma, oral corticosteroid rescues for asthma, asthma attacks, discontinuation due to worsening of asthma, and total blood peripheral eosinophil counts.

RESULTS

The most common clinical adverse experiences were upper respiratory tract infection, asthma, fever, diarrhea, and vomiting occurring with similar frequencies between treatment groups. There were no clinically meaningful differences between the two treatment groups in clinical or laboratory adverse experiences and no significant differences in frequency of patients with elevated serum transaminases. Differences between the montelukast and placebo treatment groups in the exploratory efficacy endpoints of days without beta-agonist use, oral corticosteroid rescues, emergency care, asthma attacks, and discontinuations due to worsening asthma were not significant.

CONCLUSIONS

Montelukast, 4-mg oral granules, was well tolerated over 6 weeks of treatment in children aged 6-24 months with asthma.

A population pharmacokinetic model for montelukast disposition in adults and children

PURPOSE

The purpose was to develop a population pharmacokinetic model for montelukast after intravenous administration. Clinical trial simulations were conducted using the model developed to identify the lowest intravenous dose in 6- to 14-year-old children that would give montelukast systemic exposures that were comparable to those found to be associated with efficacy in adults.

METHODS

Two clinical studies were conducted where montelukast was administered intravenously as a 7-mg dose to adults and as a 3.5-mg dose to children aged 6 to 14 years. Model development included defining the base pharmacostatistical model and investigating the effects of demographic variables [age and total body weight (TBW)] on the structural parameters, using a nonlinear mixed effect modeling approach.

RESULTS

A linear three-compartment pharmacokinetic model was found to best describe the disposition of montelukast. Inclusion of TBW as a covariate caused a 35% and 63% decrease in the interindividual variabilities on clearance and central volume of distribution, respectively. Trial simulations suggested that a 5.25-mg intravenous dose of montelukast should be chosen in children aged 6 to 14 years.

CONCLUSIONS

The model developed can adequately describe the intravenous pharmacokinetics of montelukast and can be used as a useful tool for dose selection in pediatric subpopulations.