ABSTRACT
Epidemiological studies have documented an increase in the prevalence of asthma and allergic diseases over the last 20 years, associated with an increase in morbidity and mortality, as reflected by increased hospitalizations and increased use of medications for asthma (1). Although treatment with inhaled corticosteroids and as-needed short-acting β2-adrenergic agonists maintains disease control in the majority of asthmatics, some patients remain symptomatic and require additional treatment with long-acting β2-adrenergic agonists, theophylline, leukotriene receptor antagonists, or oral corticosteroids for control of symptoms (2). There are a number of studies to support the involvement of histamine in the pathogenesis of lower airway inflammation in asthma; however, the results of clinical trials with first-generation H1-antagonists showed limited efficacy. In most countries H1-antagonists have not traditionally been prescribed for the management of asthma. Indeed, it was believed that the first-generation antihistamines could potentially exacerbate asthma by drying airway secretions as a result of anticholinergic side effects.
