β2 Agonists

Abstract

History suggests β agonists, the cognate ligand of the β2adrenoceptor, have been used as bronchodilators for around 5000 years, and β agonists remain today the frontline treatment for asthma and Chronic Obstructive Pulmonary Disease (COPD). The β agonists used clinically today are the products of significant expenditure and over a hundred year's intensive research aimed at minimising side effects and enhancing therapeutic usefulness. The respiratory physician now has a therapeutic toolbox of long acting β agonists to prophylactically manage bronchoconstriction, and short acting β agonists to relieve acute exacerbations. Despite constituting the cornerstone of asthma and COPD therapy, these drugs are not perfect; significant safety issues have led to a black box warning advising that long acting β agonists should not be used alone in patients with asthma. In addition there are a significant proportion of patients whose asthma remains uncontrolled. In this chapter we discuss the evolution of β agonist use and how the understanding of β agonist actions on their principal target tissue, airway smooth muscle, has led to greater understanding of how these drugs can be further modified and improved in the future. Research into the genetics of the β2adrenoceptor will also be discussed, as will the implications of individual DNA profiles on the clinical outcomes of β agonist use (pharmacogenetics). Finally we comment on what the future may hold for the use of β agonists in respiratory disease.

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“…It is a rapid and effective pharmacodynamic approach for drug administration to the lungs with less drug accumulation in nontargeted body parts. Due to its high level of drug safety, inhalation administration has become the most common treatment for long‐term COPD or asthma treatment (Billington, Penn, & Hall, ). While the focus has been on treating lung disease there is a direct exchange between the alveoli and the blood so drugs may enter the systemic system and potentially treat systemic disease (Labiris & Dolovich, ).…”

“…It is a rapid and effective pharmacodynamic approach for drug administration to the lungs with less drug accumulation in nontargeted body parts. Due to its high level of drug safety, inhalation administration has become the most common treatment for longterm COPD or asthma treatment (Billington, Penn, & Hall, 2016).…”

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