Pharmacology of bronchodilators used in the treatment of COPD

Novel treatments against airway inflammation in COPD based on drug repurposing

Chronic obstructive pulmonary disease (COPD) is a major cause of death and reduces quality of life that contributes to a health problem worldwide. Chronic airway inflammation is a hallmark of COPD, which occurs in response to exposure of inhaled irritants like cigarette smoke. Despite accessible to the most up-to-date medications, none of the treatments is currently available to decrease the disease progression. Therefore, it is believed that drugs which can reduce airway inflammation will provide effective disease modifying therapy for COPD. There are many broad-range anti-inflammatory drugs including those that inhibit cell signaling pathways like inhibitors of p38 mitogen-activated protein kinase (MAPK), nuclear factor-κB (NF-κB), and phosphoinositide-3-kinase (PI3K), are now in phase III development for COPD. In this chapter, we review recent basic research data in the laboratory that may indicate novel therapeutic pathways arisen from currently used drugs such as selective monoamine oxidase (MAO)-B inhibitors and drugs targeting peripheral benzodiazepine receptors [also known as translocator protein (TSPO)] to reduce airway inflammation. Considering the impact of chronic airway inflammation on the lives of COPD patients, the potential pharmacological candidates for new anti-inflammatory targets should be further investigated. In addition, it is crucial to consider the phenotypes/molecular endotypes of COPD patients together with specific outcome measures to target novel therapies. This review will enhance our knowledge on how cigarette smoke affects MAO-B activity and TSPO activation/inactivation with specific ligands through regulation of mitochondrial function, and will help to identify new potential treatment for COPD in future.

Formoterol for the Treatment of Chronic Obstructive Pulmonary Disease

Bronchodilators, including long-acting β2-agonists and long-acting muscarinic antagonists, are the mainstay for treatment of patients with chronic obstructive pulmonary disease (COPD) to prevent exacerbations or reduce symptoms. Formoterol is a highly selective and potent β2-agonist that relaxes airway smooth muscle to significantly improve lung function. Inhaled formoterol works within 5 minutes of administration and provides improvements in spirometry measurements over 12 hours. The lipophilicity of formoterol allows it to form a depot within the smooth muscle to provide a prolonged duration of action. Following therapeutic doses, plasma concentrations are very low or undetectable. Determination of the pharmacokinetics of formoterol following high-dose administration to healthy volunteers revealed that the drug was rapidly absorbed and excreted unchanged in the urine with a half-life of 10 hours. Inhaled formoterol, as monotherapy or in combination with other agents, is an effective and safe treatment option for patients with moderate to severe COPD. Clinical studies have demonstrated improvements in lung function and COPD symptoms, particularly dyspnea; reductions in the risk of exacerbations; and improvement in patients' health status. The adverse event profile of inhaled formoterol is similar to that of placebo, with few adverse cardiovascular events. Formoterol is a valuable bronchodilator used in the maintenance treatment of COPD. This review describes the mechanism of action, pharmacodynamics, and pharmacokinetics of inhaled formoterol. It also reviews the results of large, randomized, controlled clinical trials that evaluated the use of formoterol as monotherapy and in combination with inhaled corticosteroids, long-acting muscarinic antagonists, and triple therapy regimens in the treatment of patients with moderate to severe COPD.

Hybrids consisting of the pharmacophores of salmeterol and roflumilast or phthalazinone: dual β₂-adrenoceptor agonists-PDE4 inhibitors for the treatment of COPD

A novel class of dual pharmacology bronchodilators targeting both β(2)-adrenoceptor and PDE4 was designed and synthesised by combining the pharmacophores of salmeterol and roflumilast or phthalazinone. All the compounds exhibited better β(2)-adrenoceptor agonist activities (pEC(50)=8.47-9.20) than the reference compound salmeterol (pEC(50)=8.3) and good inhibitory activity on PDE4B2 (IC(50)=0.235-1.093 μM).

Developments in drugs for the treatment of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) affects more than 600 million adults worldwide and accounts for 3 million deaths annually. Approximately 50% of the cases are directly attributable to cigarette smoking; the rest are accounted for by different risk factors, including childhood infections, genetic defects, environmental pollution and biomass exposure. The mainstay of current drug treatment is bronchodilation. Anti-inflammatory drugs are reserved for patients with moderate-to-severe disease. In this article, we will review the current paradigm of COPD pathogenesis and discuss some promising molecular targets that may be modified in the future to improve health outcomes of patients with COPD.

A review of the GOLD guidelines for the diagnosis and treatment of patients with COPD

Chronic obstructive pulmonary disease (COPD) is a leading cause of death in the USA, and represents a major health, social and economic burden. COPD is underdiagnosed and often misdiagnosed, which likely contributes to the continuing increases in the prevalence, morbidity and mortality associated with this disease. This is unfortunate because whereas COPD cannot be cured, it can be treated effectively, particularly during the earlier stages of the disease. Evidence-based guidelines, developed to assist in the prevention, diagnosis and management of COPD, are available to healthcare professionals interested in learning more about COPD. These guidelines are updated and revised on a regular basis to reflect recent advances in our understanding of the pathophysiology of and treatments available for COPD. Nevertheless, primary-care physicians have reported a lack of awareness of the fundamental concepts underpinning the optimal treatment and management of COPD presented in the guidelines. Thus, the objective of this article is to summarise key physiologic, diagnostic and management concepts provided in the most recent update of the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines, which were published in November 2006.

Update on the pharmacologic therapy for chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease is a treatable disease characterized by progressive airflow limitation. Prevention of disease progression; improvement of symptoms, exercise tolerance, and health status; and decrease in exacerbations and mortality are the goals of management. Inhaled short-acting bronchodilators are recommended for symptoms in mild disease, whereas inhaled long-acting bronchodilators are recommended for maintenance therapy of daily symptoms. When symptoms are not controlled using one bronchodilator, combining bronchodilators may be more effective. Combining a long-acting beta-agonist with an inhaled corticosteroid is more effective than either agent alone. Several novel therapies are in different stages of development.

One hundred years of chronic obstructive pulmonary disease (COPD)

Chronic obstructive pulmonary disease (COPD) is an increasing health problem and one of the leading causes of morbidity and mortality worldwide, but knowledge about its pathogenesis has increased substantially in recent years. The disease results from interaction between individual risk factors (like enzymatic deficiencies) and environmental exposures to noxious agents, like cigarette smoking, occupational dusts, air pollution and infections in childhood. The main mechanisms that may contribute to airflow limitation in COPD are fixed narrowing of small airways, emphysema and luminal obstruction with mucus secretions. COPD is characterised by a chronic inflammatory process in the pulmonary tissue, with a pattern different from bronchial asthma, associated with extrapulmonary effects and is considered now a complex, systemic disease. Optimal therapeutic targeting of COPD depends on a clear understanding of the precise mechanisms of these complex processes and on early and correct evaluation of disease severity. A combination of pharmacological and non-pharmacological approaches is used to treat COPD. Bronchodilators are the mainstay of COPD treatment and can be combined with inhaled corticosteroids for greater efficacy and fewer side effects. The use of LTOT for hypoxemic patients has resulted in increased survival, and expanded drug therapy options have effectively improved dyspnoea and quality of life. Recent studies have documented the benefits of pulmonary rehabilitation. In addition, non-invasive mechanical ventilation offers new alternatives for patients with acute or chronic failure.

Long-acting inhaled beta 2-agonists for stable COPD

OBJECTIVE

To describe the pathogenesis of chronic obstructive pulmonary disease (COPD) and mechanisms of benefit, formulations available, drug costs, pharmacokinetic profiles, and pertinent clinical studies for long-acting beta(2)-agonists.

DATA SOURCES

A MEDLINE search was conducted from July 1966 through October 2002.

STUDY SELECTION AND DATA EXTRACTION

Pertinent articles related to COPD and long-acting beta(2)-agonists.

DATA SYNTHESIS

The incidence and subsequent morbidity and mortality of COPD have increased during the last 4 decades, prompting worldwide initiatives to formulate guidelines to decrease the burden of this disease. COPD is a progressive, irreversible disease state characterized by chronic cough, dyspnea, sputum production, and wheezing, in which no medication has been shown to decrease mortality, excluding oxygen supplementation. Bronchodilators have been a mainstay of COPD treatment through their ability to work by both smooth- and non-smooth-muscle mechanisms. Long-acting beta(2)-agonists (i.e., formoterol, salmeterol) dosed twice daily provide more convenient dosing than 4-times-daily regimens of traditional short-acting bronchodilators. Both formoterol and salmeterol have acceptable adverse event profiles when used at recommended doses. There have been no direct clinical outcome studies comparing formoterol and salmeterol, but both have shown some benefits over ipratropium and theophylline in improving the symptoms, spirometric indices, exacerbations, and quality of life of patients with COPD.

CONCLUSIONS

Based on current evidence, long-acting beta(2)-agonists are acceptable first-line agents for patients with COPD.

Addition of an extra dose of salmeterol Diskus to conventional dose of salmeterol Diskus in patients with COPD

Patients experiencing dyspnoea can request an additional dose of salmeterol during the dose interval for the control of their symptoms, although under treatment with salmeterol. In this study we have explored the effects on respiratory function of an additive dose of salmeterol Diskus in 15 chronic obstructive pulmonary disease (COPD) patients in regular treatment with a conventional dose of 50 microg salmeterol. On two different days, patients inhaled 50 microg Diskus. After 240 min, they inhaled additional 50 microg salmeterol Diskus (salmeterol arm) or placebo Diskus (placebo arm). Lung function was controlled before first drug administration and 0.5, 1, 2, 3, 4, 4.5, 6, 8, 10, and 12 h thereafter. The mean (95% CI) peak increase in FEV1 from baseline was reached after 4 h in the salmeterol arm (0.174 L; 0.144-0204) and after 5 h (0.141 L; 0.115-0.168) inthe placebo arm; after 12 h, the mean (95% Cl) increase in FEV1 from basal values was still 0.149 L (0.119-0.179) in salmeterol arm, but only 0.041 L (0.017-0.064) in placebo arm. The mean (95% CI) FEV1 AUC0-12h for all patients were 2.01 (1.72-2.30) L when salmeterol was added and 1.30 (1.03-1.58) L when placebo was inhaled. The difference (mean; 95% CI) between the FEV1 AUC0-12h of the two arms (0.71 L; 0.47-0.95) was statistically significant (P<0.0001), although the difference (mean; 95% CI) between the FEV1 AUC0-4h of the two treatments (0.08 L; -0.02-0.18) was notstatistically significant (P=0.126). The addition of an extra dose of salmeterol did not significantly increase the heart rate or decrease the SpO2. This study suggests that the addition of an extra dose of salmeterol does not give room for further increase in peak FEV1, but the effect of adding salmeterol to salmeterol is largely additive when considering the duration of action and safe.