Asthma therapy over 100 years.

Abstract

100 years ago, the main treatments for asthma were the sympathomimetic ephedrine, theophylline tablets, inhaled anticholinergics in the form of "asthma cigarettes". Together with adrenaline injections for acute exacerbations, these treatments were all bronchodilators derived from natural products. Adrenaline injections evolved into inhaled β2-agonists as the most effective bronchodilators in asthma, whereas theophylline and inhaled anticholinergics are less useful treatments. The efficacy of desiccated adrenal glands extract, used since 1900, is likely due to steroids derived from the adrenal cortex. Corticosteroids are the most effective treatment for asthma and target the underlying eosinophilic airway inflammation. Combination inhalers of corticosteroid and long-acting β2-agonist are now the mainstay of asthma therapy. Recently, short-acting β2-agonists as relievers have been replaced by relievers containing an inhaled corticosteroid, together with a rapid onset long-acting β2-agonist formoterol (anti-inflammatory reliever). This addresses the major issue of poor adherence with inhaled corticosteroids. Poor inhaler technique is being addressed with the development of smart inhalers. In patients with severe asthma not controlled by inhaled therapy, antibodies that block cytokines involved in eosinophilic inflammation have been very effective. In the future, longer acting antibodies will simplify the treatment of these patients. New drugs are also in development for severe non-eosinophilic asthma. There have been remarkable advances in asthma therapy over the last century, although our current treatments have their origins in the therapies used in 1925.