Histamine and indirect bronchoprovocation with adenosine monophosphate in asthma

Modern histamine H1-receptor antagonists such as desloratadine, fexofenadine, and levocetirizine at clinically recommended doses as either monotherapy or add-on therapy to inhaled corticosteroids have been shown to attenuate bronchial hyperresponsiveness leading to significant improvement in the provocative concentration of adenosine monophosphate causing a 20% fall in forced expiratory volume in 1s compared to placebo.2-4 Therefore, although the study serve to strengthen the fact that adenosine monophosphate acts indirectly by releasing cysteinyl-leukotrienes from primed mast cells, the findings of the authors should not be interpreted as casting doubt as to the involvement of histamine in mediating the response following indirect bronchial challenge testing.