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Effect of daily dosing with tiotropium against methacholine induced bronchoconstriction in asthmatics. Pulm Pharmacol Ther 2022; 77:102174. [DOI: 10.1016/j.pupt.2022.102174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/20/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022]
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Cardet JC, Jiang X, Lu Q, Gerard N, McIntire K, Boushey HA, Castro M, Chinchilli VM, Codispoti CD, Dyer AM, Holguin F, Kraft M, Lazarus S, Lemanske RF, Lugogo N, Mauger D, Moore WC, Moy J, Ortega VE, Peters SP, Smith LJ, Solway J, Sorkness CA, Sumino K, Wechsler ME, Wenzel S, Israel E. Loss of bronchoprotection with ICS plus LABA treatment, β-receptor dynamics, and the effect of alendronate. J Allergy Clin Immunol 2019; 144:416-425.e7. [PMID: 30872116 PMCID: PMC6950766 DOI: 10.1016/j.jaci.2019.01.049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 12/14/2018] [Accepted: 01/23/2019] [Indexed: 11/15/2022]
Abstract
BACKGROUND Loss of bronchoprotection (LOBP) with a regularly used long-acting β2-adrenergic receptor agonist (LABA) is well documented. LOBP has been attributed to β2-adrenergic receptor (B2AR) downregulation, a process requiring farnesylation, which is inhibited by alendronate. OBJECTIVE We sought to determine whether alendronate can reduce LABA-associated LOBP in inhaled corticosteroid (ICS)-treated patients. METHODS We conducted a randomized, double-blind, placebo-controlled, parallel-design, proof-of-concept trial. Seventy-eight participants with persistent asthma receiving 250 μg of fluticasone twice daily for 2 weeks were randomized to receive alendronate or placebo while initiating salmeterol for 8 weeks. Salmeterol-protected methacholine challenges (SPMChs) and PBMC B2AR numbers (radioligand binding assay) and signaling (cyclic AMP ELISA) were assessed before randomization and after 8 weeks of ICS plus LABA treatment. LOBP was defined as a more than 1 doubling dose reduction in SPMCh PC20 value. RESULTS The mean doubling dose reduction in SPMCh PC20 value was 0.50 and 0.27 with alendronate and placebo, respectively (P = .62). Thirty-eight percent of participants receiving alendronate and 33% receiving placebo had LOBP (P = .81). The after/before ICS plus LABA treatment ratio of B2AR number was 1.0 for alendronate (P = .86) and 0.8 for placebo (P = .15; P = .31 for difference between treatments). The B2AR signaling ratio was 0.89 for alendronate (P = .43) and 1.02 for placebo (P = .84; P = .44 for difference). Changes in lung function and B2AR number and signaling were similar between those who did and did not experience LOBP. CONCLUSION This study did not find evidence that alendronate reduces LABA-associated LOBP, which relates to the occurrence of LOBP in only one third of participants. LOBP appears to be less common than presumed in concomitant ICS plus LABA-treated asthmatic patients. B2AR downregulation measured in PBMCs does not appear to reflect LOBP.
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Affiliation(s)
| | - Xiaofeng Jiang
- Departments of Environmental Health, Genetics & Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Mass
| | - Quan Lu
- Departments of Environmental Health, Genetics & Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Mass
| | - Norma Gerard
- Department of Pediatrics, Boston Children's Hospital, Boston, Mass
| | - Kristen McIntire
- Department of Medicine, Brigham and Women's Hospital, Boston, Mass
| | - Homer A Boushey
- Department of Medicine, University of California San Francisco, San Francisco, Calif
| | - Mario Castro
- Department of Medicine, Washington University, St Louis, Mo
| | - Vernon M Chinchilli
- Department of Public Health Sciences, Penn State College of Medicine, Hershey, Pa
| | - Christopher D Codispoti
- Department of Medicine, Rush University Medical Center and Department of Pediatrics, Stroger Hospital of Cook County, Chicago, Ill
| | - Anne-Marie Dyer
- Department of Public Health Sciences, Penn State College of Medicine, Hershey, Pa
| | | | - Monica Kraft
- Department of Medicine, University of Arizona, Tucson, Ariz
| | - Stephen Lazarus
- Department of Medicine, University of California San Francisco, San Francisco, Calif
| | - Robert F Lemanske
- Departments of Medicine and Pharmacy Practice, University of Wisconsin, Madison, Wis
| | - Njira Lugogo
- Department of Medicine, Duke University, Durham, NC
| | - Dave Mauger
- Department of Public Health Sciences, Penn State College of Medicine, Hershey, Pa
| | - Wendy C Moore
- Department of Internal Medicine, Wake Forest University, Winston-Salem, NC
| | - James Moy
- Department of Medicine, Rush University Medical Center and Department of Pediatrics, Stroger Hospital of Cook County, Chicago, Ill
| | - Victor E Ortega
- Department of Internal Medicine, Wake Forest University, Winston-Salem, NC
| | - Stephen P Peters
- Department of Internal Medicine, Wake Forest University, Winston-Salem, NC
| | - Lewis J Smith
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Julian Solway
- Department of Medicine, University of Chicago, Chicago, Ill
| | - Christine A Sorkness
- Departments of Medicine and Pharmacy Practice, University of Wisconsin, Madison, Wis
| | - Kaharu Sumino
- Department of Medicine, Washington University, St Louis, Mo
| | | | - Sally Wenzel
- Department of Medicine, Pittsburgh University, Pittsburgh, Pa
| | - Elliot Israel
- Department of Medicine, Brigham and Women's Hospital, Boston, Mass.
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Martin N, Weiler JM, Pearlman D, Jacques L, Nunn C, Forth R, West S, Dunn K, O'Byrne PM. Fluticasone furoate/vilanterol versus fluticasone propionate in patients with asthma and exercise-induced bronchoconstriction. J Asthma 2019; 57:431-440. [PMID: 30795705 DOI: 10.1080/02770903.2019.1579344] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Objective: To investigate whether once-daily (OD) fluticasone furoate (FF)/vilanterol (VI) provides greater long-term protection from postexercise fall in forced expiratory volume in 1 s (FEV1) than twice-daily (BD) fluticasone propionate (FP) in patients with asthma and exercise-induced bronchoconstriction. Methods: A randomized, double-blind, crossover study was conducted in patients (aged 12-50 years) on low-/mid-dose maintenance inhaled corticosteroid. Following a 4-week run-in period (FP 250 µg BD), patients with a ≥ 20% decrease in postexercise FEV1 received FF/VI 100/25 µg OD or FP 250 µg BD for 2 weeks. Exercise challenges were carried out 23 h after the first dose of study medication, and 12 and 23 h after evening clinic dose at the end of the 2-week treatment period. After a 2-week washout period (FP 250 µg), patients crossed over treatments, with procedures and tests repeated. The primary endpoint was mean maximal percentage decrease from pre-exercise FEV1 following exercise challenge 12-h postevening dose on Day 14. Results: The mean maximal percentage decrease from pre-exercise FEV1 after the 12-h exercise challenge (Day 14) was 15.02% with FF/VI, and 16.71% with FP (difference, -1.69; 95% confidence interval, -3.76 to 0.39; p = 0.109). After the 23-h exercise challenge (Day 14), respective mean maximal decreases were 11.90% and 14.05% (difference, -2.15; 95% confidence interval, -4.31 to 0.01). Conclusion: The study failed to show a difference between FF/VI and FP at providing long-term protection from exercise-induced bronchoconstriction.
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Affiliation(s)
- Neil Martin
- Glenfield Hospital, University Hospitals of Leicester, Leicester, UK.,GSK, London, UK
| | | | - David Pearlman
- Colorado Allergy and Asthma Centers PC, Denver, CO, USA.,University of Colorado School of Medicine, Aurora, CO, USA
| | | | | | | | | | - Karen Dunn
- North Carolina Clinical Research, Raleigh, NC, USA
| | - Paul M O'Byrne
- Firestone Institute for Respiratory Health, Hamilton, ON, Canada.,Michael G DeGroote School of Medicine, McMaster University, Hamilton, ON, Canada
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Weiler JM, Brannan JD, Randolph CC, Hallstrand TS, Parsons J, Silvers W, Storms W, Zeiger J, Bernstein DI, Blessing-Moore J, Greenhawt M, Khan D, Lang D, Nicklas RA, Oppenheimer J, Portnoy JM, Schuller DE, Tilles SA, Wallace D. Exercise-induced bronchoconstriction update-2016. J Allergy Clin Immunol 2016; 138:1292-1295.e36. [PMID: 27665489 DOI: 10.1016/j.jaci.2016.05.029] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 05/13/2016] [Accepted: 05/25/2016] [Indexed: 12/26/2022]
Abstract
The first practice parameter on exercise-induced bronchoconstriction (EIB) was published in 2010. This updated practice parameter was prepared 5 years later. In the ensuing years, there has been increased understanding of the pathogenesis of EIB and improved diagnosis of this disorder by using objective testing. At the time of this publication, observations included the following: dry powder mannitol for inhalation as a bronchial provocation test is FDA approved however not currently available in the United States; if baseline pulmonary function test results are normal to near normal (before and after bronchodilator) in a person with suspected EIB, then further testing should be performed by using standardized exercise challenge or eucapnic voluntary hyperpnea (EVH); and the efficacy of nonpharmaceutical interventions (omega-3 fatty acids) has been challenged. The workgroup preparing this practice parameter updated contemporary practice guidelines based on a current systematic literature review. The group obtained supplementary literature and consensus expert opinions when the published literature was insufficient. A search of the medical literature on PubMed was conducted, and search terms included pathogenesis, diagnosis, differential diagnosis, and therapy (both pharmaceutical and nonpharmaceutical) of exercise-induced bronchoconstriction or exercise-induced asthma (which is no longer a preferred term); asthma; and exercise and asthma. References assessed as relevant to the topic were evaluated to search for additional relevant references. Published clinical studies were appraised by category of evidence and used to document the strength of the recommendation. The parameter was then evaluated by Joint Task Force reviewers and then by reviewers assigned by the parent organizations, as well as the general membership. Based on this process, the parameter can be characterized as an evidence- and consensus-based document.
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Pera T, Hegde A, Deshpande DA, Morgan SJ, Tiegs BC, Theriot BS, Choi YH, Walker JKL, Penn RB. Specificity of arrestin subtypes in regulating airway smooth muscle G protein-coupled receptor signaling and function. FASEB J 2015; 29:4227-35. [PMID: 26103985 DOI: 10.1096/fj.15-273094] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 06/15/2015] [Indexed: 12/22/2022]
Abstract
Arrestins have been shown to regulate numerous G protein-coupled receptors (GPCRs) in studies employing receptor/arrestin overexpression in artificial cell systems. Which arrestin isoforms regulate which GPCRs in primary cell types is poorly understood. We sought to determine the effect of β-arrestin-1 or β-arrestin-2 inhibition or gene ablation on signaling and function of multiple GPCRs endogenously expressed in airway smooth muscle (ASM). In vitro [second messenger (calcium, cAMP generation)], ex vivo (ASM tension generation in suspended airway), and in vivo (invasive airway resistance) analyses were performed on human ASM cells and murine airways/whole animal subject to β-arrestin-1 or -2 knockdown or knockout (KO). In both human and murine model systems, knockdown or KO of β-arrestin-2 relative to control missense small interfering RNA or wild-type mice selectively increased (40-60%) β2-adrenoceptor signaling and function. β-arrestin-1 knockdown or KO had no effect on signaling and function of β2-adrenoceptor or numerous procontractile GPCRs, but selectively inhibited M3 muscarinic acetylcholine receptor signaling (∼50%) and function (∼25% ex vivo, >50% in vivo) without affecting EC50 values. Arrestin subtypes differentially regulate ASM GPCRs and β-arrestin-1 inhibition represents a novel approach to managing bronchospasm in obstructive lung diseases.
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Affiliation(s)
- Tonio Pera
- *Department of Medicine, Division of Pulmonary and Critical Care Medicine, Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; and Division of Pulmonary, Allergy, and Critical Care Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Akhil Hegde
- *Department of Medicine, Division of Pulmonary and Critical Care Medicine, Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; and Division of Pulmonary, Allergy, and Critical Care Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Deepak A Deshpande
- *Department of Medicine, Division of Pulmonary and Critical Care Medicine, Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; and Division of Pulmonary, Allergy, and Critical Care Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Sarah J Morgan
- *Department of Medicine, Division of Pulmonary and Critical Care Medicine, Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; and Division of Pulmonary, Allergy, and Critical Care Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Brian C Tiegs
- *Department of Medicine, Division of Pulmonary and Critical Care Medicine, Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; and Division of Pulmonary, Allergy, and Critical Care Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Barbara S Theriot
- *Department of Medicine, Division of Pulmonary and Critical Care Medicine, Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; and Division of Pulmonary, Allergy, and Critical Care Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Yeon H Choi
- *Department of Medicine, Division of Pulmonary and Critical Care Medicine, Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; and Division of Pulmonary, Allergy, and Critical Care Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Julia K L Walker
- *Department of Medicine, Division of Pulmonary and Critical Care Medicine, Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; and Division of Pulmonary, Allergy, and Critical Care Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Raymond B Penn
- *Department of Medicine, Division of Pulmonary and Critical Care Medicine, Center for Translational Medicine, Jane and Leonard Korman Lung Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; and Division of Pulmonary, Allergy, and Critical Care Medicine, Duke University Medical Center, Durham, North Carolina, USA
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Rosethorne EM, Bradley ME, Kent TC, Charlton SJ. Functional desensitization of the β 2 adrenoceptor is not dependent on agonist efficacy. Pharmacol Res Perspect 2015; 3:e00101. [PMID: 25692019 PMCID: PMC4317232 DOI: 10.1002/prp2.101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 09/10/2014] [Accepted: 09/11/2014] [Indexed: 11/24/2022] Open
Abstract
Chronic treatment with β 2 adrenoceptor agonists is recommended as a first-line maintenance therapy for chronic obstructive pulmonary disease (COPD). However, a potential consequence of long-term treatment may be the loss of functional response (tachyphylaxis) over time. In this study, we have investigated the tendency of such agonists, with a range of efficacies, to develop functional desensitization to cAMP responses in primary human bronchial smooth muscle cells following prolonged agonist exposure. The data show that upon repeat exposure, all agonists produced functional desensitization to the same degree and rate. In addition, β 2 adrenoceptor internalization and β-arrestin-2 recruitment were monitored using β 2·eGFP visualization and the PathHunter™ β-arrestin-2 assay, respectively. All agonists were capable of causing robust receptor internalization and β-arrestin-2 recruitment, the rate of which was influenced by agonist efficacy, as measured in those assays. In summary, although a relationship exists between agonist efficacy and the rate of both receptor internalization and β-arrestin-2 recruitment, there is no correlation between agonist efficacy and the rate or extent of functional desensitization.
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Affiliation(s)
- Elizabeth M Rosethorne
- Novartis Institutes for Biomedical ResearchWimblehurst Road, Horsham, West Sussex, RH12 5AB, United Kingdom
- School of Life Sciences, Queen’s Medical Centre, University of NottinghamNottingham, NG7 2UH, United Kingdom
| | - Michelle E Bradley
- Novartis Institutes for Biomedical ResearchWimblehurst Road, Horsham, West Sussex, RH12 5AB, United Kingdom
| | - Toby C Kent
- Novartis Institutes for Biomedical ResearchWimblehurst Road, Horsham, West Sussex, RH12 5AB, United Kingdom
| | - Steven J Charlton
- Novartis Institutes for Biomedical ResearchWimblehurst Road, Horsham, West Sussex, RH12 5AB, United Kingdom
- School of Life Sciences, Queen’s Medical Centre, University of NottinghamNottingham, NG7 2UH, United Kingdom
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Impaired Bronchoprotection Is Not Induced by Increased Smooth Muscle Mass in Chronic Treatment In Vivo with Formoterol in Asthmatic Mouse Model. ACTA ACUST UNITED AC 2015; 63:641-6. [PMID: 25803396 DOI: 10.7727/wimjopen.2014.177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 08/11/2014] [Indexed: 02/05/2023]
Abstract
OBJECTIVE Inhaling β2-adrenoceptor agonist is first-line asthma treatment, which is used for both acute relief of and prevention of bronchoconstriction. However, chronic use of β-agonists results in impaired bronchoprotection and increasing occurrences of severe asthma exacerbation, even death in clinical practice. The mechanism of β-adrenoceptor hyposensitivity has not been thoroughly elucidated thus far. Bronchial smooth muscle contraction induces airway narrowing and also mediates airway inflammation. Moreover, bronchial smooth muscle mass significantly increases in asthmatics. We aim to establish an asthmatic model that demonstrated that formoterol induced impaired bronchoprotection and to see whether increased smooth muscle mass play a role in it. METHODS We combined routine allergen challenging (seven weeks) with repeated application of formoterol, formoterol plus budesonide or physiological saline in allergen-sensitized BALB/c mouse. The bronchoprotection mediated by β-agonist was measured in five consecutive weeks. Smooth muscle mass was shown by morphometric analysis, and α-actin expression was detected by western blot. RESULTS The trend of bronchoprotection was wavy in drug interventional groups, which initially increased and then decreased. Chronic treatment with formoterol significantly impaired bronchoprotection. According to the morphometric analysis and α-actin expression, no significant difference was detected in smooth muscle mass in all groups. CONCLUSION This experiment successfully established that a chronic asthmatic mouse model, which manifested typical features of asthmatic patients, when treated chronically with formoterol, resulted in a loss of bronchoprotection. No significant difference was detected in smooth muscle mass in all groups, which implied some subcellular signalling changes may be the key points.
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Cockcroft DW, Sears MR. Are inhaled longacting β2 agonists detrimental to asthma? THE LANCET RESPIRATORY MEDICINE 2013; 1:339-46. [PMID: 24429159 DOI: 10.1016/s2213-2600(13)70044-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Possible adverse effects of adrenergic bronchodilators in asthma have been the subject of discussion for more than half a century, with recent intense debate about the safety of longacting β agonists (LABAs). In this Debate, we consider the issues of bronchodilator and bronchoprotective tolerance resulting from the frequent use of bronchodilators, which is noted particularly with shortacting drugs, but has also been shown to occur quicker and to a greater extent with LABAs. Increased allergen responsiveness and masking allowing inflammation to increase, while symptoms and lung function remain apparently controlled, have also been observed. Studies in which LABAs were used as monotherapy were associated with increased mortality. However, several studies have shown the benefits of adding LABAs to inhaled corticosteroids (ICS). Meta-analyses of asthma clinical trials involving LABAs showed that, when given with mandatory ICS, LABAs were not associated with an increased risk of death, intubations, or hospital admission for exacerbations when compared with use of the same dose of ICS only. Withdrawal of LABA therapy once symptom control is achieved is often associated with subsequent loss of symptom control. When used for appropriate indications, LABAs should be combined with ICS in one inhaler so that monotherapy is not possible.
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Affiliation(s)
- Donald W Cockcroft
- University of Saskatchewan, Royal University Hospital, Department of Medicine, Division of Respirology, Critical Care and Sleep Medicine, Saskatoon, SK, Canada.
| | - Malcolm R Sears
- McMaster University/St Joseph's Hospital, Firestone Institute for Respiratory Health, Hamilton, ON, Canada
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Walker JKL, Kraft M, Fisher JT. Assessment of murine lung mechanics outcome measures: alignment with those made in asthmatics. Front Physiol 2013; 3:491. [PMID: 23408785 PMCID: PMC3569663 DOI: 10.3389/fphys.2012.00491] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 12/17/2012] [Indexed: 01/13/2023] Open
Abstract
Although asthma is characterized as an inflammatory disease, recent reports highlight the importance of pulmonary physiology outcome measures to the clinical assessment of asthma control and risk of asthma exacerbation. Murine models of allergic inflammatory airway disease have been widely used to gain mechanistic insight into the pathogenesis of asthma; however, several aspects of murine models could benefit from improvement. This review focuses on aligning lung mechanics measures made in mice with those made in humans, with an eye toward improving the translational utility of these measures. A brief description of techniques available to measure murine lung mechanics is provided along with a methodological consideration of their utilization. How murine lung mechanics outcome measures relate to pulmonary physiology measures conducted in humans is discussed and we recommend that, like human studies, outcome measures be standardized for murine models of asthma.
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Affiliation(s)
- Julia K L Walker
- Division of Pulmonary, Allergy and Critical Care Medicine, Duke University Medical Center Durham, NC, USA
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Stewart SL, Martin AL, Davis BE, Cockcroft DW. Salbutamol tolerance to bronchoprotection: course of onset. Ann Allergy Asthma Immunol 2012. [PMID: 23176887 DOI: 10.1016/j.anai.2012.08.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
BACKGROUND Regular use of inhaled β-agonist leads to tolerance to its bronchoprotective effect. This occurs within 12 hours with salmeterol and has been documented at 1 week for salbutamol. The course of onset after introduction of salbutamol has not been investigated. OBJECTIVE To determine the course of onset of tolerance to the bronchoprotective effect of salbutamol against methacholine. METHODS Thirteen individuals with mild asthma completed a randomized, double-blind, placebo-controlled, cross-over study. Each treatment period consisted of 7 twice-daily doses (2 puffs of 100 μg of salbutamol or placebo). Methacholine challenges were conducted 24 hours apart on 4 consecutive days, 10 minutes after the first, third, fifth, and seventh doses. The 2 treatment periods were separated by at least 14 days. RESULTS Methacholine provocation concentration that caused a decrease in forced expiratory volume in 1 second of 20% (PC(20)) values during the 4 days of placebo treatment did not significantly differ (analysis of variance P = .79). A single dose of salbutamol shifted the methacholine PC(20) approximately 5-fold from a geometric mean of 2.1 mg/mL to a geometric mean of 10.7 mg/mL. Maximal bronchoprotection after the active treatment occurred on day 2 after the third dose, which was significantly higher than on day 1 after the first dose (P = .04). After the fifth dose the methacholine PC(20) was trending downward, and on day 4 the bronchoprotective effect of salbutamol had significantly decreased from its peak protection (P = .001). CONCLUSION The detrimental effects on bronchoprotection after regular use of salbutamol manifest after 5 doses and are significantly reduced from peak protection after 7 doses. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01338311.
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Affiliation(s)
- Sarah L Stewart
- Department of Medicine, Division of Respirology, Critical Care, and Sleep Medicine, University of Saskatchewan, Saskatoon, Canada
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11
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Lin R, Degan S, Theriot BS, Fischer BM, Strachan RT, Liang J, Pierce RA, Sunday ME, Noble PW, Kraft M, Brody AR, Walker JKL. Chronic treatment in vivo with β-adrenoceptor agonists induces dysfunction of airway β(2) -adrenoceptors and exacerbates lung inflammation in mice. Br J Pharmacol 2012; 165:2365-77. [PMID: 22013997 DOI: 10.1111/j.1476-5381.2011.01725.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE Inhalation of a β-adrenoceptor agonist (β-agonist) is first-line asthma therapy, used for both prophylaxis against, and acute relief of, bronchoconstriction. However, repeated clinical use of β-agonists leads to impaired bronchoprotection and, in some cases, adverse patient outcomes. Mechanisms underlying this β(2) -adrenoceptor dysfunction are not well understood, due largely to the lack of a comprehensive animal model and the uncertainty as to whether or not bronchorelaxation in mice is mediated by β(2) -adrenoceptors. Thus, we aimed to develop a mouse model that demonstrated functional β-agonist-induced β(2) -adrenoceptor desensitization in the context of allergic inflammatory airway disease. EXPERIMENTAL APPROACH We combined chronic allergen exposure with repeated β-agonist inhalation in allergen-treated BALB/C mice and examined the contribution of β(2) -adrenoceptors to albuterol-induced bronchoprotection using FVB/NJ mice with genetic deletion of β(2) -adrenoceptors (KO). Associated inflammatory changes - cytokines (ELISA), cells in bronchoalevolar lavage and airway remodelling (histology) and β(2) -adrenoceptor density (radioligand binding) - were also measured. KEY RESULTS β(2) -Adrenoceptors mediated albuterol-induced bronchoprotection in mice. Chronic treatment with albuterol induced loss of bronchoprotection, associated with exacerbation of the inflammatory components of the asthma phenotype. CONCLUSIONS AND IMPLICATIONS This animal model reproduced salient features of human asthma and linked loss of bronchoprotection with airway pathobiology. Accordingly, the model offers an advanced tool for understanding the mechanisms of the effects of chronic β- agonist treatment on β-adrenoceptor function in asthma. Such information may guide the clinical use of β-agonists and provide insight into development of novel β-adrenoceptor ligands for the treatment of asthma.
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Affiliation(s)
- Rui Lin
- Duke University Medical Center, Durham, NC, USA
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12
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Weiler JM, Anderson SD, Randolph C, Bonini S, Craig TJ, Pearlman DS, Rundell KW, Silvers WS, Storms WW, Bernstein DI, Blessing-Moore J, Cox L, Khan DA, Lang DM, Nicklas RA, Oppenheimer J, Portnoy JM, Schuller DE, Spector SL, Tilles SA, Wallace D, Henderson W, Schwartz L, Kaufman D, Nsouli T, Shieken L, Rosario N. Pathogenesis, prevalence, diagnosis, and management of exercise-induced bronchoconstriction: a practice parameter. Ann Allergy Asthma Immunol 2011; 105:S1-47. [PMID: 21167465 DOI: 10.1016/j.anai.2010.09.021] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 09/26/2010] [Indexed: 02/06/2023]
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Charlton SJ. Agonist efficacy and receptor desensitization: from partial truths to a fuller picture. Br J Pharmacol 2010; 158:165-8. [PMID: 19719779 DOI: 10.1111/j.1476-5381.2009.00352.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
It has been demonstrated that the degree of agonist-induced desensitization of the beta(2)-adrenoceptor is related to agonist efficacy (strength of signalling), whereby high-efficacy agonists (e.g. formoterol) cause more phosphorylation and internalization of the receptor than low-efficacy agonists (e.g. salmeterol). These early studies, however, used a protocol where agonists were matched for receptor occupancy rather than functional effect. In this issue of the BJP, Duringer and colleagues have extended these studies to compare the ability of agonists to cause desensitization at equi-effective (cAMP signalling) concentrations rather than equal occupancy. Their data and conclusions are quite different from those previously described. After prolonged exposure, all the agonists caused a similar degree of desensitization, whereas a pulse protocol uncovered a greater loss of responsiveness with the low-efficacy ligands. This is consistent with the notion that high-efficacy agonists have 'spare receptors', and are therefore less sensitive to loss of receptors through desensitization. It also reflects experience in the clinic, where both formoterol and salmeterol show a similar early decline in bronchoprotection, after which their effects remain stable. These findings challenge the notion that high-efficacy ligands always cause more functional desensitization.
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Page CP, Spina D. Beta2-agonists and bronchial hyperresponsiveness. Clin Rev Allergy Immunol 2007; 31:143-62. [PMID: 17085790 DOI: 10.1385/criai:31:2:143] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/11/2022]
Abstract
Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma, and individuals with this disease respond to a range of physiological and chemical insults that are otherwise innocuous to healthy subjects, suggesting that the mechanisms underlying this phenomenon are characteristic of the asthma phenotype. BHR can be increased following exposure to environmental allergens in suitably sensitized individuals, pollutants, and certain viruses and can also be exacerbated by exposure to certain drugs, including nonsteroidal anti-inflammatory agents and beta-blockers. Although beta2-agonists administered acutely remain the treatment for the symptoms of asthma, paradoxically, regular treatment with these drugs can result in an increase in BHR, and this has been suggested to contribute to the increase in asthma morbidity and mortality that has been reported by numerous investigators. This article highlights our current understanding of this phenomenon and examines the potential mechanisms responsible for this effect.
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Affiliation(s)
- Clive P Page
- Sackler Institute of Pulmonary Pharmacology, School of Biomedical and Health Sciences, King's College London, United Kingdom.
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15
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Cockcroft DW. Clinical concerns with inhaled beta2-agonists: adult asthma. Clin Rev Allergy Immunol 2007; 31:197-208. [PMID: 17085793 DOI: 10.1385/criai:31:2:197] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/11/2022]
Abstract
Inhaled beta2-agonists, when used regularly, cause subtle but significant worsening of asthma control. Overuse of inhaled beta2-agonists is associated with increased risk of death from asthma in a dose-response fashion. beta2-Agonists enhance airway responses to allergens, including induced airway hyperresponsiveness and induced airway inflammation. This is a plausible explanation for beta2-agonist-worsened asthma control. These direct effects of inhaled beta2-agonists, including increased airway response to allergen, tolerance, etc., may partially explain the association of overuse with asthma death. However, it is probable that the major reason for the association of beta2-agonists overuse and asthma mortality is an indirect effect. Inhaled beta2-agonists are effective relievers and preventers of bronchoconstriction and asthma symptoms but fail to treat the underlying pathogenesis, namely the airway inflammation. Thus, overuse may mask the true asthma severity and result in both an underappreciation and undertreatment of the disease. This would provide a rational explanation for the relationship of inhaled beta2-agonist use and mortality and also would fit the dose-response pattern. Inhaled beta2-agonists should be used exclusively as needed for relief of symptoms and their requirement should be infrequent: the need for excessive doses of beta2-agonists provides a useful marker of asthma (lack of) control.
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Affiliation(s)
- D W Cockcroft
- Division of Respirology, Critical Care and Sleep Medicine, Department of Medicine, Royal University Hospital/University of Saskatchewan, Saskatoon, Canada.
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Tsagaraki V, Amfilochiou A, Markantonis SL. Evidence of tachyphylaxis associated with salmeterol treatment of chronic obstructive pulmonary disease patients. Int J Clin Pract 2006; 60:415-21. [PMID: 16620353 DOI: 10.1111/j.1368-5031.2006.00849.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Bronchodilator therapy is lifelong mandatory for chronic obstructive pulmonary disease patients. There is evidence of loss of bronchodilator effectiveness over time with beta2-agonists but not with anticholinergics. The aim of this study was to examine the development of tachyphylaxis to the long-acting beta2-agonist salmeterol using as a control therapeutic regimen the combination of ipratropium bromide and salbutamol sulphate. Fifty-six subjects participated in a 20-week, crossover randomised clinical trial. The parameters forced expiratory volume at 1 s (FEV1), peak expiratory flow rate (PEFR) and FEV1/forced vital capacity were measured via spirometry and the parameters triangle DeltaFEV1%pre, triangle DeltaPEFR%pre and triangle DeltaAUC(0-2 h) were calculated. FEV1 increased significantly after two weeks of treatment with the combination treatment but not with the salmeterol. The observed diminished increase could be attributed to the development of tolerance to the long acting beta2-agonist. Salmeterol seems to be an effective bronchodilator, however, its duration of action over time and its peak effect might be subject to tachyphylaxis.
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Affiliation(s)
- V Tsagaraki
- School of Pharmacy, Laboratory of Biopharmaceutics and Pharmacokinetics, University of Athens, Athens, Greece
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17
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Ek A, Palmberg L, Sundblad BM, Larsson K. Salmeterol Does Not Alter Increased Bronchial Responsiveness Caused by Organic Dust Exposure. Chest 2005; 128:3038-47. [PMID: 16236984 DOI: 10.1378/chest.128.4.3038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Exposure in a swine house induces airway inflammation and increases bronchial responsiveness to methacholine in healthy subjects. STUDY OBJECTIVES The aim was to investigate whether a long-acting beta2-agonist, salmeterol, alters the increased bronchial responsiveness induced in healthy subjects following exposure to organic dust in a swine barn. DESIGN AND SUBJECTS The study includes three separate parts. In the first part (part 1), healthy subjects inhaled salmeterol (50 microg bid, n = 8) or placebo (n = 8) over 2 weeks. In part 2, healthy subjects inhaled one single dose of salmeterol (100 microg, n = 6) or placebo (n = 6) 1 h prior to exposure in a swine barn, which was followed by a bronchial methacholine challenge. In part 3, eight healthy individuals inhaled placebo or salmeterol (100 microg), 2 h or 8 h prior to a bronchial methacholine provocation, without being exposed in the swine barn. RESULTS Exposure caused an increase of bronchial responsiveness to methacholine by 3.2 doubling concentration steps (25 to 75th percentiles, 2.8 to 4.1) and 2.6 doubling concentration steps (25 to 75th percentiles, 1.4 to 3.7) in the placebo and salmeterol groups (2 weeks), respectively, with no significant differences between the groups (p = 0.3; part 1). Similar results were obtained when salmeterol was administered as a single dose (part 2) prior to exposure. However, salmeterol significantly attenuated the bronchial responsiveness to methacholine by 1.2 doubling concentration steps (0.8 to 1.7) 8 h after inhalation (part 3). CONCLUSIONS Salmeterol inhalation did not protect against the increased bronchial responsiveness induced in healthy subjects following exposure to organic dust when administered for 2 weeks or as a single dose prior to exposure. This lack of protection cannot be explained by homologous beta2-adrenoceptor desensitization. We hypothesize that exposure to organic material may alter the airway response to beta2-agonists.
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Affiliation(s)
- Alexandra Ek
- Lung and Allergy Research, Division of Pathology, Institute of Environmental Medicine, Karolinska Institutet, PO Box 287, SE-171 77 Stockholm, Sweden
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18
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van der Woude HJ, Aalbers R. Long-acting beta2-agonists: comparative pharmacology and clinical outcomes. ACTA ACUST UNITED AC 2005; 1:55-74. [PMID: 14720076 DOI: 10.1007/bf03257163] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Salmeterol and formoterol are both long-acting beta(2)-adrenoceptor agonists (beta(2)-agonists). They both provide excellent bronchodilating and bronchoprotective effects in patients with asthma but their are some differences between these two long-acting beta(2)-agonists in vitro and in vivo. Formoterol has a greater potency and intrinsic activity than salmeterol, which can become especially apparent at higher doses than that clinically recommended, and in contracted bronchi. Long-term use of long-acting beta(2)-agonists can induce tolerance, which can be partially reversed with corticosteroids. Long-acting beta(2)-agonists have some anti-inflammatory effects in vitro, but data in vivo are less convincing. Compared with doubling the dose of inhaled corticosteroids, the addition of inhaled long-acting beta(2)-agonists to inhaled corticosteroids improves symptom control in patients with asthma and reduces both the exacerbation rate of asthma and hospital admission rate. No enhanced airway responsiveness or loss of perception of dyspnea has been observed with the use of inhaled long-acting beta(2)-agonists. Monotherapy with long-acting beta(2)-agonists is not recommended.
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Affiliation(s)
- Hanneke J van der Woude
- Department of Pulmonary Diseases, Martini Hospital, Postbus 30033, 9700 RM Groningen, The Netherlands.
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Abstract
INTRODUCTION Regular use of beta-agonists leads to tolerance to their bronchodilator effects. This is easily demonstrated if dilation is tested following methacholine challenge. It is not known how quickly tolerance develops or how long it lasts after stopping beta-agonist therapy. METHODS Ten subjects with stable asthma were studied. Following 2 weeks without beta-agonists, methacholine was inhaled to induce a 20% reduction in FEV1. The response to inhaled salbutamol (100, 100, 200 microg at 5-min intervals) was then measured. This procedure was repeated 24 h after one dose and 24 h after 3, 7 and 14 days of inhaled formoterol 12 microg twice daily, and 3 and 5 days after formoterol was discontinued. Unscheduled use of beta-agonists was not permitted. RESULTS Bronchodilator tolerance, assessed by a reduction of the area under the salbutamol dose-response curve, occurred after 1 dose of formoterol (28% reduction, 95% CI 12, 45%), increased up to 1 week and plateaued between 1 and 2 weeks (58% reduction, 95% CI 38, 78%). Three days after stopping formoterol, the response to salbutamol was similar to baseline (12% reduction, 95% CI -9, 33%). The first dose of formoterol provided significant bronchoprotection to methacholine (1.6 doubling doses, P=0.007). This diminished with regular treatment and by 2 weeks the PD20 methacholine was not significantly different to baseline. CONCLUSIONS Bronchodilator tolerance occurs after a single dose and reaches a maximum after 1 week of regular formoterol. Sensitivity recovers 3 days after stopping treatment.
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Affiliation(s)
- Sarah Haney
- Department of Respiratory Medicine, Waikato Hospital, Hamilton, New Zealand
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20
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Dente FL, Bacci E, Bartoli ML, Cianchetti S, Di Franco A, Giannini D, Taccola M, Vagaggini B, Paggiaro PL. One week treatment with salmeterol does not prevent early and late asthmatic responses and sputum eosinophilia induced by allergen challenge in asthmatics. Pulm Pharmacol Ther 2004; 17:147-53. [PMID: 15123224 DOI: 10.1016/j.pupt.2004.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2003] [Revised: 12/22/2003] [Accepted: 01/26/2004] [Indexed: 11/30/2022]
Abstract
Salmeterol is an effective long-acting beta(2)-agonist bronchodilator, able to inhibit, as a single dose, asthmatic responses induced by several stimuli including allergen, and the subsequent increase in sputum eosinophilia. Aim of the present study was to investigate whether these effects of salmeterol persisted after 1 week of continuous treatment, or whether a loss of the bronchoprotective effects of salmeterol can occur over time. We investigated in a cross-over double blind placebo-controlled study, the protective effect of 1 week treatment with salmeterol on allergen-induced early and late responses and the associated airway inflammation in 15 atopic asthmatic subjects. Eosinophil percentage and Eosinophil Cationic Protein (ECP) concentration in peripheral blood and in hypertonic saline induced sputum were measured at baseline and 24 h after allergen inhalation. Salmeterol partially inhibited early asthmatic response, but it did not inhibit late asthmatic response in comparison with placebo. Salmeterol did not inhibit also the increase in sputum eosinophils percentage 24 h after allergen inhalation (E%, median: 22.7 and 15%, after placebo and after salmeterol respectively, p=n.s. between two post-allergen sputum samples). Also, the increase in blood eosinophils and both sputum and serum ECP at 24 h after allergen challenge was not affected by salmeterol pre-treatment. In conclusion, 1 week treatment with salmeterol causes a loss of its protective effect on allergen-induced airway bronchoconstriction, and does not prevent the subsequent increase in sputum and serum eosinophilic markers.
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Affiliation(s)
- F L Dente
- Sezione di Pneumologia, Dipartimento Cardio-Toracico, Ospedale di Cisanello, Fisiopatologia Respiratoria Universitaria, via Paradisa 2, Universitá di Pisa, 56100 Pisa, Italy.
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21
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Abstract
The use of a regular long-acting beta2-adrenoceptor agonists (beta2-agonists; LABA) is now established in asthma guidelines as the preferred option for second-line controller therapy in addition to inhaled corticosteroids. This has been driven by data showing beneficial effects of LABAs on exacerbation rates, in turn suggesting a putative corticosteroid-sparing effect. As LABAs are devoid of any clinically meaningful anti-inflammatory activity in vivo, their effects on exacerbations are presumably due to a diurnal stabilising effect on airway smooth muscle. LABAs have marked effects on symptoms and lung function, and this may make it difficult to assess anti-inflammatory control with inhaled corticosteroids when used in a combination inhaler such as fluticasone propionate/salmeterol or budesonide/formoterol. The use of fixed-dose combination inhalers is in many respects counter-intuitive to conventional teaching regarding flexible dosage titration with inhaled corticosteroids. It would therefore seem prudent first to gain optimal control of inflammation with inhaled corticosteroids before considering adding a LABA. Increasing the dosage of inhaled corticosteroids will have a relatively greater effect on exacerbations than on symptoms and lung function, whereas the converse applies when adding a LABA. Another option is to add a leukotriene receptor antagonist, which confers additional anti-inflammatory activity and is as effective on exacerbations as adding a LABA. Despite in vitro and ex vivo data showing a ligand-independent effect of LABAs on glucocorticoid receptor activation, clinical data do not indicate any relevant synergy between LABAs and inhaled corticosteroids when used together in the same inhaler. In particular, there is no evidence of potentiation by LABAs of the in vivo anti-inflammatory activity of inhaled corticosteroids that would suggest any genuine corticosteroid-sparing activity. Nonetheless, the data support the additive effects of inhaled corticosteroids and LABAs when used together due to their separate effects on inflammation and smooth muscle, respectively. Tolerance with LABAs is a predictable pharmacological phenomenon that occurs despite concomitant therapy with inhaled corticosteroids. Moreover, cross-tolerance also develops to short-acting beta2-agonists used for protection against bronchoconstrictor stimuli as a result of LABA-induced down-regulation, desensitisation and prolonged occupancy of beta2-adrenoceptors. The exact role of beta2-adrenoceptor polymorphism in determining tolerance with LABAs requires further prospective clinical studies evaluating long-term effects on outcomes such as exacerbations in patients with relevant genotypes and haplotypes. The next decade will provide challenging issues for clinicians with respect to defining further the role of LABAs as add-on controller therapy, particularly in evaluating the long-term effects of combination inhalers on inflammatory outcomes and airway remodelling.
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Affiliation(s)
- Catherine M Jackson
- Tayside Centre for General Practice and Asthma and Allergy Research Group, Department of Medicine and Therapeutics, University of Dundee, Ninewells Hospital and Medical School, Dundee, Scotland
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22
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Lee DKC, Currie GP, Hall IP, Lima JJ, Lipworth BJ. The arginine-16 beta2-adrenoceptor polymorphism predisposes to bronchoprotective subsensitivity in patients treated with formoterol and salmeterol. Br J Clin Pharmacol 2004; 57:68-75. [PMID: 14678342 PMCID: PMC1884417 DOI: 10.1046/j.1365-2125.2003.01955.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AIMS The relationship between beta2-adrenoceptor polymorphisms and bronchoprotective response with long-acting beta2-adrenoceptor agonists is unknown. METHODS We retrospectively analysed data from six placebo-controlled randomized studies in corticosteroid treated asthmatics where formoterol or salmeterol were administered over a 1-2-week period, with prior 1-2 week washout, assessing the primary end point of methacholine PD20 and adenosine monophosphate PC20, following first and last dose, expressed as doubling dose difference from placebo. RESULTS There was no significant heterogeneity between the different studies. Patients who had homozygous or heterozygous genotypes containing the arginine-16 polymorphism (Arg16-Arg16 or Arg16-Gly16) had greater bronchoprotective subsensitivity compared with the homozygous glycine-16 genotype (Gly16-Gly16), amounting to a mean doubling dose difference of 1.49 (95% CI 0.50, 2.48), after the last dose. Subsensitivity of response was greater with formoterol than salmeterol after the last dose in all genotypes, especially with the arginine-16 polymorphism, amounting to a doubling dose difference of 3.00 (95% CI 1.01, 4.99) between formoterol and salmeterol. CONCLUSIONS Our retrospective analysis showed that the arginine-16 polymorphism was associated with subsensitivity of response for bronchoprotection, which was greater for formoterol than salmeterol. A prospective study will be required in order to further evaluate these findings, particularly to assess whether these differences are mirrored by exacerbations.
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Affiliation(s)
- Daniel K C Lee
- Asthma & Allergy Research Group, Department of Clinical Pharmacology, Ninewells Hospital & Medical School, University of Dundee, Dundee DD1 9SY, Scotland, UK
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23
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Abstract
The established place of regular long-acting beta2-adrenoceptor agonists at step 3 in asthma management guidelines has evolved as a consequence of evidence showing additive effects of salmeterol and formoterol on exacerbation rates, resulting in a putative inhaled corticosteroid sparing effect. There is however, evidence to show that although long-acting beta2-adrenoceptor agonists facilitate using a lower dose of inhaled corticosteroid, this may occur at the expense of suboptimal anti-inflammatory control. This is likely to be the case especially with fixed dose combination inhalers where it is not possible to properly titrate anti-inflammatory therapy with inhaled corticosteroids without also inadvertently overtreating with unnecessarily high doses of long-acting beta2-adrenoceptor agonists. Most patients with mild to moderate persistent asthma can be adequately controlled on monotherapy with inhaled corticosteroid in low or medium dosage, which is considerably cheaper than concomitant use of a long-acting beta2-adrenoceptor agonist. Subsensitivity to long-acting beta2-adrenoceptor agonists is a predictable pharmacological phenomenon which occurs despite concomitant inhaled corticosteroid therapy and occurs more readily for bronchoprotective than bronchodilator effects. Subsensitivity of salbutamol protection against bronchoconstrictor stimuli occurs in patients receiving concomitant long-acting beta2-adrenoceptor agonists, which may be due to beta2-adrenoceptor down-regulation or prolonged receptor occupancy. Prospective large scale long-term studies are required to further define the clinical relevance of beta2-adrenoceptor polymorphisms, to look at clinical control outcomes as well as propensity for subsensitivity. It would therefore make more sense to first of all optimize the dose of anti-inflammatory therapy with inhaled corticosteroid and to then consider adding a long-acting beta2-adrenoceptor agonist for patients who are poorly controlled.
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Affiliation(s)
- Brian J Lipworth
- Asthma and Allergy Research Group, Department of Clinical Pharmacology & Therapeutics, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY UK.
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Hancox RJ, Taylor DR. Long-acting beta-agonist treatment in patients with persistent asthma already receiving inhaled corticosteroids. BioDrugs 2001; 15:11-24. [PMID: 11437672 DOI: 10.2165/00063030-200115010-00002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
International guidelines recommend that long-acting beta-agonists should be considered in patients who are symptomatic despite moderate doses of inhaled corticosteroids. When combined with inhaled corticosteroids they improve asthma symptoms and lung function and reduce exacerbations. The evidence suggests that they are well tolerated. However, they are less effective than inhaled corticosteroids as monotherapy and should not be used alone, although the addition of a long-acting beta-agonist may permit a small reduction in the corticosteroid dose. Both salmeterol and formoterol appear equally effective in improving asthma control. Formoterol, however, has a rapid onset of action and is now being promoted for the relief of acute asthma symptoms. Both drugs provide prolonged protection against exercise-induced bronchospasm. However, this effect rapidly diminishes with continuous therapy and if this is the main aim of treatment, intermittent use may be preferable. When compared with alternative treatments, inhaled long-acting beta-agonists are more effective in controlling asthma symptoms than either theophylline or antileukotriene agents. Bambuterol, an oral prodrug of terbutaline, appears to be as effective as the inhaled long-acting beta-agonists and has the advantage of once daily oral administration. However, the inhaled long-acting beta-agonists are less likely to have systemic adverse effects. There are theoretical concerns that regular beta-agonist treatment may lead to tolerance and a failure to respond to emergency asthma treatment. While there is no doubt that tolerance occurs, there is currently little evidence that this is a clinical problem. Insights into pharmacological as well as therapeutic interactions between inhaled corticosteroids and beta-agonists are providing justification for their use in combination. Guidelines for the management of patients with chronic persistent asthma are likely to require modification to reflect these developments.
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Affiliation(s)
- R J Hancox
- Department of Medical and Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
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Jones SL, Cowan JO, Flannery EM, Hancox RJ, Herbison GP, Taylor DR. Reversing acute bronchoconstriction in asthma: the effect of bronchodilator tolerance after treatment with formoterol. Eur Respir J 2001; 17:368-73. [PMID: 11405513 DOI: 10.1183/09031936.01.17303680] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Continuous treatment with a short-acting beta2-agonist can lead to reduced bronchodilator responsiveness during acute bronchoconstriction. This study evaluated bronchodilator tolerance to salbutamol following regular treatment with a long-acting beta2-agonist, formoterol. The modifying effect of intravenous corticosteroid was also studied. Ten asthmatic subjects (using inhaled steroids) participated in a randomised, double-blind, placebo-controlled, cross-over study. Formoterol 12 microg b.i.d. or matching placebo was given for 10-14 days with >2 weeks washout. Following each treatment, patients underwent a methacholine challenge to induce a fall in forced expired volume in one second (FEV1) of at least 20%, then salbutamol 100 microg, 100 microg, and 200 microg was inhaled via a spacer at 5 min intervals, with a further 400 microg at 45 min. After a third single-blind formoterol treatment period, hydrocortisone 200 mg was given intravenously prior to salbutamol. Dose-response curves for change in FEV1 with salbutamol were compared using analysis of covariance to take account of methacholine-induced changes in spirometry. Regular formoterol resulted in a significantly lower FEV1 after salbutamol at each time point compared to placebo (p<0.01). The area under the curves (AUCs) for 15 (AUC0-15) and 45 (AUC0-45) min were 28.8% and 29.5% lower following formoterol treatment (p<0.001). Pretreatment with hydrocortisone had no significant modifying effect within 2 h of administration. It is concluded that significant tolerance to the bronchodilator effects of inhaled salbutamol occurs 36 h after stopping the regular administration of formoterol. This bronchodilator tolerance is evident in circumstances of acute bronchconstriction.
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Affiliation(s)
- S L Jones
- Dept of Medical and Surgical Sciences, Dunedin School of Medicine, University of Otago, New Zealand
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26
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Finney PA, Donnelly LE, Belvisi MG, Chuang TT, Birrell M, Harris A, Mak JCW, Scorer C, Barnes PJ, Adcock IM, Giembycz MA. Chronic systemic administration of salmeterol to rats promotes pulmonary beta(2)-adrenoceptor desensitization and down-regulation of G(s alpha). Br J Pharmacol 2001; 132:1261-70. [PMID: 11250877 PMCID: PMC1572675 DOI: 10.1038/sj.bjp.0703946] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. The aim of the present study was to examine the effects of chronic infusion of the long-acting agonist salmeterol on pulmonary beta(2)-adrenoceptor function in Sprague-Dawley rats in vivo and to elucidate the molecular basis of any altered state. 2. Systemic administration of rats with salmeterol for 7 days compromised the ability of salmeterol and prostaglandin E(2) (PGE(2)), given acutely by the intravenous route, to protect against ACh-induced bronchoconstriction when compared to rats treated identically with vehicle. 3. beta(1)- and beta(2)-adrenoceptor density was significantly reduced in lung membranes harvested from salmeterol-treated animals, which was associated with impaired salmeterol- and PGE(2)-induced cyclic AMP accumulation ex vivo. 4. Three variants of G(s alpha) that migrated as 42, 44 and 52 kDa peptides on SDS polyacrylamide gels were detected in lung membranes prepared from both groups of rats but the intensity of each isoform was markedly reduced in rats that received salmeterol. 5. The activity of cytosolic, but not membrane-associated, G-protein receptor-coupled kinase was elevated in the lung of salmeterol-treated rats when compared to vehicle-treated animals. 6. The ability of salmeterol, administered systemically, to protect the airways of untreated rats against ACh-induced bronchoconstriction was short-acting (t(off) approximately 45 min), which contrasts with its long-acting nature when given to asthmatic subjects by inhalation. 7. These results indicate that chronic treatment of rats with salmeterol results in heterologous desensitization of pulmonary G(s)-coupled receptors. In light of previous data obtained in rats treated chronically with salbutamol, we propose that a primary mechanism responsible for this effect is a reduction in membrane-associated G(s alpha). The short-acting nature of salmeterol, when administered systemically, and the reduction in beta-adrenoceptor number may be due to metabolism to a biologically-active, short-acting and non-selective beta-adrenoceptor agonist.
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MESH Headings
- Acetylcholine/pharmacology
- Adrenergic beta-Agonists/administration & dosage
- Adrenergic beta-Agonists/pharmacology
- Albuterol/administration & dosage
- Albuterol/analogs & derivatives
- Albuterol/pharmacology
- Animals
- Bronchoconstriction/drug effects
- Cyclic AMP/metabolism
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Dinoprostone/pharmacology
- Down-Regulation
- Drug Interactions
- GTP-Binding Protein alpha Subunits, Gi-Go/biosynthesis
- GTP-Binding Protein alpha Subunits, Gs/biosynthesis
- Gene Expression/drug effects
- Injections, Intravenous
- Lung/drug effects
- Lung/metabolism
- Male
- Protective Agents/pharmacology
- RNA, Messenger/drug effects
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Adrenergic, beta-1/genetics
- Receptors, Adrenergic, beta-1/metabolism
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/metabolism
- Salmeterol Xinafoate
- beta-Adrenergic Receptor Kinases
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Affiliation(s)
- Paul A Finney
- Thoracic Medicine, National Heart & Lung Institute, Imperial College School of Medicine, London
| | - Louise E Donnelly
- Thoracic Medicine, National Heart & Lung Institute, Imperial College School of Medicine, London
| | - Maria G Belvisi
- Cardiothoracic Surgery, National Heart & Lung Institute, Imperial College School of Medicine, London
| | - Tsu-Tshen Chuang
- GlaxoWellcome Research and Development, Medicines Research Centre, Stevenage, Hertfordshire
| | - Mark Birrell
- Cardiothoracic Surgery, National Heart & Lung Institute, Imperial College School of Medicine, London
| | - Andrew Harris
- GlaxoWellcome Research and Development, UK Research BioMet, Ware, Hertfordshire
| | - Judith C W Mak
- Thoracic Medicine, National Heart & Lung Institute, Imperial College School of Medicine, London
| | - Carol Scorer
- GlaxoWellcome Research and Development, Medicines Research Centre, Stevenage, Hertfordshire
| | - Peter J Barnes
- Thoracic Medicine, National Heart & Lung Institute, Imperial College School of Medicine, London
| | - Ian M Adcock
- Thoracic Medicine, National Heart & Lung Institute, Imperial College School of Medicine, London
| | - Mark A Giembycz
- Thoracic Medicine, National Heart & Lung Institute, Imperial College School of Medicine, London
- Author for correspondence:
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27
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Grootendorst DC, Sterk PJ, Heijerman HG. Effect of oral prednisolone on the bronchoprotective effect of formoterol in patients with persistent asthma. Eur Respir J 2001; 17:374-9. [PMID: 11405514 DOI: 10.1183/09031936.01.17303740] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Tolerance to the bronchoprotective effects by long-acting beta2-agonists (LAB) in patients with asthma is not prevented by inhaled corticosteroids (ICS). This study examined whether oral prednisolone can restore the bronchoprotective effects of formoterol in 24 patients with persistent asthma already treated with ICS (at least 800 microg budesonide x day(-1) or equivalent) and LAB, using a parallel-group design. During a 2-week run-in period and during the study, patients used formoterol 12 microg twice daily by Turbuhaler, instead of their own LAB. At baseline and at the end of 7-days treatment with oral placebo or prednisolone (30 mg x day(-1)), provocative concentration of histamine causing a 20% fall in forced expiratory volume in one second (PC20 histamine) was measured on two separate days after randomized single-dose inhalation of placebo (postP) or formoterol (postF). In addition, PC20postF was measured 24 h after starting oral treatment. The protective effect by formoterol at baseline and during treatment was calculated as the difference between the logs of PC20postP and PC20postF. The mean+/-SEM in doubling dose (DD) bronchoprotective effect at baseline was 0.8+/-0.4 DD in the placebo group and 1.0+/-0.4 DD in the prednisolone group. At the end of the treatment period, the protective effect changed to 1.0+/-0.5 DD and 0.8+/-0.6 DD in the placebo and prednisolone treated groups, respectively. This change was not different between the groups (p > 0.4). In conclusion, the bronchoprotective effect by formoterol is not influenced by 1 week prednisolone treatment in patients with asthma who are using regular inhaled corticosteroids and long-acting beta2-agonists. These findings indicate that tolerance to long-acting beta2-agonists cannot be restored by oral steroid therapy.
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Affiliation(s)
- D C Grootendorst
- Dept of Pulmonology, Leijenburg Hospital, The Hague, The Netherlands
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Quadrelli SA, Roncoroni AJ, Pinna DM. [Beta-agonists in the treatment of bronchial asthma]. Arch Bronconeumol 2000; 36:471-84. [PMID: 11004989 DOI: 10.1016/s0300-2896(15)30128-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- S A Quadrelli
- Instituto de Investigaciones Médicas Alfredo Lanari, Universidad de Buenos Aires.
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Lipworth BJ, Dempsey OJ, Aziz I. Functional antagonism with formoterol and salmeterol in asthmatic patients expressing the homozygous glycine-16 beta(2)-adrenoceptor polymorphism. Chest 2000; 118:321-8. [PMID: 10936119 DOI: 10.1378/chest.118.2.321] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Formoterol and salmeterol differ in their relative intrinsic activity at airway beta(2)-adrenoceptors, with formoterol being a full agonist. The homozygous glycine-16 polymorphism of the beta(2)-adrenoceptor occurs in approximately 40% of patients and is known to predispose to agonist-induced downregulation and desensitization. OBJECTIVES To evaluate possible differences in intrinsic beta(2)-adrenoceptor agonist activity between salmeterol and formoterol in terms of their functional antagonism against methacholine-induced bronchoconstriction (the primary end point) in genetically susceptible patients who exhibited the homozygous glycine-16 polymorphism. METHODS Eighteen patients with mild-to-moderate persistent asthma receiving inhaled corticosteroid who expressed the homozygous glycine-16 genotype were randomized to completion (mean [SEM] age, 35.8 [3.2] years; mean FEV(1), 76.9 [2. 5]% predicted). Patients received three different treatments for 1 week in randomized, double-blind, crossover fashion, with a 1-week washout period between treatments: formoterol, 12 microg bid; salmeterol, 50 microg bid; and placebo. For each of the randomized treatment periods, there were three separate methacholine challenges: baseline after washout, 12 h after the first dose, and 12 h after the last dose. RESULTS Both salmeterol and formoterol exhibited significantly (p < 0.05) greater bronchoprotection than placebo for their effects after single or repeated dosing, although there was no significant difference between the two drugs. The geometric mean fold protection vs placebo (95% confidence interval [CI]) for the first dose was 1.6-fold (95% CI, 1.1 to 2.2) for salmeterol and 1.9-fold (95% CI, 1.1 to 3.2) for formoterol, and for last dose was 1.6-fold (95% CI, 1.2 to 2.3) for salmeterol and 1. 9-fold (95% CI, 1.2 to 2.8) for formoterol. Salmeterol and formoterol produced significant (p < 0.05) increases in FEV(1) and forced expiratory flow after 25 to 75% of vital capacity has been expelled, after the first but not the last dose compared to placebo, while there were significant (p < 0.05) improvements in domiciliary peak flows during treatment with both drugs. CONCLUSION Our results showed no difference between formoterol and salmeterol in the degree of functional antagonism against methacholine-induced bronchoconstriction at the end of a 12-h dosing interval in patients who expressed the homozygous glycine-16 genotype. There was a significant residual degree of bronchoprotection after 1 week of treatment, which was not significantly different compared to the first-dose effect.
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Affiliation(s)
- B J Lipworth
- Asthma and Allergy Research Group, Department of Clinical Pharmacology & Therapeutics, Ninewells Hospital and Medical School, University of Dundee, Scotland, UK.
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Abstract
OBJECTIVE To review the pharmacology, pharmacokinetics, clinical efficacy, and adverse effects of montelukast, a leukotriene receptor antagonist used to treat asthma, and to discuss the therapeutic role of montelukast as long-term medication and difficulties associated with the management of asthma. DATA SOURCES A MEDLINE search (up to May 1999) was conducted to identify relevant English-language publications, including preclinical studies, clinical trials, and recent reviews. STUDY SELECTION All available published reports of controlled, clinical trials of montelukast in adults and children with asthma were summarized, including pharmacokinetic and pharmacologic effects of montelukast. DATA EXTRACTION Information on the safety and efficacy of montelukast was evaluated on the basis of patient selection, study design, methodology, and statistical significance as compared with placebo or inhaled corticosteroid treatment. DATA SYNTHESIS Montelukast is approved for the prophylaxis and chronic treatment of asthma at a dose of 10 mg once daily for adolescents (> or =15 y) and adults and 5 mg once daily for children (6-14 y). In placebo-controlled clinical trials, montelukast significantly improved pulmonary lung function (as measured by forced expiratory volume in 1 sec), significantly reduced beta2-agonist use, and significantly improved patient-reported end points in adults and children (> or =6 y) with chronic asthma. In adults, a similar magnitude of improvement in lung function is seen with or without inhaled corticosteroid use; the effects of montelukast may be additive to those of inhaled corticosteroids and permit the reduction of the required dose of inhaled corticosteroids. In cases of exercise-induced asthma (adults and children), montelukast treatment attenuates the fall in pulmonary function following exercise. It attenuates both the early- and late-phase responses of asthma after allergen inhalation. Improvements in asthma control are similar in asthmatic patients who are aspirin-sensitive or not aspirin-sensitive and can be seen within one day of treatment. Tolerance does not develop, and the adverse events do not differ from those of placebo. CONCLUSIONS Montelukast is indicated for the prophylaxis of chronic asthma in adults and children (> or =6 y). It may be considered for use as first-line therapy in patients with mild persistent asthma or for additional control in patients who are still symptomatic while receiving treatment with inhaled corticosteroids. It may also be used for additional control in aspirin-sensitive asthmatic patients. Consideration may be given for using montelukast to allow tapering of the dose of inhaled corticosteroids while maintaining clinical stability. Chronic treatment with montelukast can provide additional control of symptoms during exercise, but inhaled beta2-agonists remain first-line therapy for prophylaxis and treatment.
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Affiliation(s)
- K V Blake
- Nemours Children's Clinic, Jacksonville, FL 32207, USA.
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Villaran C, O'Neill SJ, Helbling A, van Noord JA, Lee TH, Chuchalin AG, Langley SJ, Gunawardena KA, Suskovic S, Laurenzi M, Jasan J, Menten J, Leff JA. Montelukast versus salmeterol in patients with asthma and exercise-induced bronchoconstriction. Montelukast/Salmeterol Exercise Study Group. J Allergy Clin Immunol 1999; 104:547-53. [PMID: 10482826 DOI: 10.1016/s0091-6749(99)70322-2] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Montelukast, a leukotriene receptor antagonist, and salmeterol, a long-acting beta(2)-receptor agonist, each have demonstrated benefits in the treatment of exercise-induced bronchoconstriction (EIB) in short-term studies. Direct comparisons between these agents in long-term studies are limited. OBJECTIVE We sought to compare montelukast and salmeterol in the long-term treatment of EIB. METHODS One hundred ninety-seven patients with mild asthma and a postexercise fall in FEV(1) of at least 18% were randomized (double-blind) to receive montelukast 10 mg once daily or salmeterol 50 microg twice daily for 8 weeks. Exercise challenge was repeated at day 3, week 4, and week 8 after randomization near the end of the dosing interval for both drugs. The primary efficacy endpoint was the maximal percent fall in postexercise FEV(1) at week 8. RESULTS Montelukast was effective in treating EIB without inducing tolerance and provided superior (P </=.001) protection than salmeterol at weeks 4 and 8, with comparable protection at day 3. The frequency of respiratory clinical adverse events (P =.046) and discontinuations because of clinical adverse events (P =.052) were less with montelukast. CONCLUSION The effect of montelukast was greater than that of salmeterol in the chronic treatment of EIB over a period of 8 weeks in patients with mild asthma as demonstrated by effect size, maintenance of effect, and fewer respiratory clinical adverse events during the study period. Montelukast may be a better alternative to salmeterol as a controller agent for the chronic treatment of EIB.
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Aziz I, Lipworth BJ. In vivo effect of albuterol on methacholine-contracted bronchi in conjunction with salmeterol and formoterol. J Allergy Clin Immunol 1999; 103:816-22. [PMID: 10329815 DOI: 10.1016/s0091-6749(99)70425-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND It has been shown in vitro that prior treatment with salmeterol and formoterol antagonizes the relaxant effect of albuterol in carbachol-contracted human bronchi. OBJECTIVES The primary aim of this study was to evaluate whether there is a potential in vivo interaction between long- and short-acting beta2-agonists in the presence of increased airway tone induced by methacholine. In addition, a post hoc analysis was made to evaluate the effects of beta2-adrenoceptor polymorphisms. METHODS Sixteen asthmatic subjects (mean age [+/-SD], 39 [13] years; FEV1, 81% [17%] of predicted value), all taking inhaled corticosteroids and having methacholine PD20 values of less than 500 micrograms, were randomized in double-blind, double-dummy, cross-over fashion to receive single doses of inhaled placebo, inhaled formoterol 12 micrograms, or inhaled salmeterol 50 micrograms followed 12 hours later by a single dose of inhaled albuterol 400 micrograms (low dose) or 1600 micrograms (high dose). Methacholine challenges were performed on each of 6 separate occasions 1 hour after albuterol. RESULTS There was a greater numerical difference in geometric mean PD20 values between low- and high-dose albuterol after placebo dosing (671 micrograms vs 1080 micrograms, a 1.61-fold difference; P <.05) compared with low- and high-dose albuterol after formoterol dosing (660 micrograms vs 799 micrograms, a 1. 21-fold difference; P =.4), or after salmeterol dosing (568 micrograms vs 847 micrograms, a 1.49-fold difference; P =.055). PD20 values with high-dose albuterol in combination with formoterol or salmeterol were numerically lower than those found with high-dose albuterol in combination with placebo, but they were not significantly different. There was a significant difference between PD20 values with low-dose albuterol after dosing with formoterol (PD20 = 660 micrograms, a 1. 6-fold difference; P <.05) or with salmeterol (PD20 = 568 micrograms, a 1.9-fold difference; P <.05) compared with PD20 with high-dose albuterol after placebo dosing (PD20 = 1080 micrograms). Post hoc polymorphism analysis for pooled pretreatment with formoterol and salmeterol (excluding placebo pretreatment) showed significantly (P <.05) lower PD20 values with homozygous glycine-16 compared with heterozygous glycine/arginine-16 and significantly (P <.05) lower PD20 values with homozygous glutamate-27 compared with either heterozygous glutamate/glutamine-27 or homozygous glutamine-27. CONCLUSION Compared with placebo, both salmeterol and formoterol caused a significant degree of antagonism of albuterol-induced bronchorelaxation in methacholine-contracted bronchi in vivo. This interaction could be caused by prolonged occupancy of airway beta2-adrenoceptors by long-acting beta2-agonists or by early tachyphylaxis 12 hours after a single-dose exposure. The degree of albuterol protection was also related to beta2-adrenoceptor polymorphism.
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Affiliation(s)
- I Aziz
- Department of Clinical Pharmacology and Therapeutics and the Department of Respiratory Medicine, Ninewells Hospital and Medical School, University of Dundee, Scotland, UK
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