It is now evident that patients with asthma or chronic obstructive pulmonary disease (COPD) can also benefit from the use of fixed-dose combinations, including combinations of a long-acting β2-agonist and an inhaled corticosteroid, and combinations of long-acting β2-agonists and long-acting muscarinic receptor antagonists. In fact, there are now a number of “triple-inhaler” fixed-dose combinations under development, with the first such triple combination having been approved.
Although asthma and COPD have many similarities, they also have many differences. COPD is not asthma. Asthma is not COPD. They have:
- Different etiology;
- Different symptoms;
- Different type of airway inflammation;
- Different inflammatory cells;
- Different mediators;
- Different consequences of inflammation;
- Different response to therapy;
- Different course.
This use of combinations containing drugs with complementary pharmacological actions in the treatment of patients with asthma or COPD has also led to the discovery and development of drugs having two different primary pharmacological actions in the same molecule, which we have called “bifunctional drugs”. In this review, we discuss the state of the art of these new bifunctional drugs as novel treatments for asthma and COPD that can be categorised as bifunctional bronchodilators, bifunctional bronchodilator/anti-inflammatory drugs and bifunctional anti-inflammatory drugs.
COPD can coexist with asthma; both are characterized by an underlying airway inflammation. The underlying chronic airway inflammation is very different in these two diseases. However, individuals with asthma who are exposed to noxious agents, particularly cigarette smoke may develop fixed airflow limitation and a mixture of “asthma -like” and “COPD-like” inflammation. Furthermore, there is epidemiologic evidence that longstanding asthma on its own can lead to fixed airflow limitation. Other patients with COPD may have features of asthma such as a mixed inflammatory pattern with increased eosinophils. Thus, while asthma can usually be distinguished from COPD, in some individuals with chronic respiratory symptoms and fixed airflow limitation it remains difficult to differentiate the two diseases.
Bronchial asthma and COPD (chronic obstructive pulmonary disease) are obstructive pulmonary diseases that affected millions of people all over the world. Asthma is a serious global health problem with an estimated 300 million affected individuals. COPD is one of the major causes of chronic morbidity and mortality and one of the major public health problems worldwide. COPD is the fourth leading cause of death in the world and further increases in its prevalence and mortality can be predicted. Although asthma and COPD have many similarities, they also have many differences. They are two different diseases with differences in etiology, symptoms, type of airway inflammation, inflammatory cells, mediators, consequences of inflammation, response to therapy, course. Some similarities in airway inflammation in severe asthma and COPD and good response to combined therapy in both of these diseases suggest that they have some similar pathophysiologic characteristics. The aim of this article is to show similarities and differences between these two diseases.
Asthma and COPD are usually differentiated :
- Different inflammatory cells
- Different inflammatory mediators
- Different response to therapy
- “Reversible COPD” (asthma coexists)
- Severe asthma
- Asthma in smokers
- Neutrophil asthma (asthma in smokers, non-allergic asthma)
- allergic asthma
- acute exacerbation
Today asthma and COPD are not fully curable, not identified enough and not treated enough and the therapy is still developing. But in future better understanding of pathology, adequate identifying and treatment, may be and new drugs, will provide a much better quality of life, reduced morbidity and mortality of these patients.
An alternative approach to delivering complementary pharmacological activities for the treatment of patients with asthma or COPD is to develop molecules specifically designed to have two distinct primary pharmacological actions based on distinct pharmacophores, which we will term bifunctional drugs. Bronchial asthma and COPD are obstructive pulmonary diseases that affected millions of people all over the world. Although asthma and COPD have many differences, they also have some similarities. They are two different diseases with differences in etiology, symptoms, type of airway inflammation, inflammatory cells, mediators, consequences of inflammation, response to therapy, course. Some similarities in airway inflammation in severe asthma and COPD and good response to combined therapy (LABA/ ICS) in both these diseases suggest that they have similar pathophysiologic characteristics. Today asthma and COPD are not fully curable, not identified enough and not treated enough and the therapy is still developing. But in future better understanding of pathology, adequate identifying and treatment, perhaps and new drugs will provide a much better quality of life, reduced morbidity and mortality of these patients. These are not to be confused with drugs that can exhibit multiple mechanisms of action that may all contribute to clinical effectiveness (e.g. glucocorticosteroids, xanthines or statins) as, while it is recognised that some drugs having multiple effects have been the starting point for the development of bifunctional drugs, they were not intentionally developed to have multiple actions via distinct mechanisms.