Histamine-Induced Bronchospasm.

Publisher Website
Google Scholar
Abstract
The reproducibility of the histamine challenge in 7 asymptomatic patients with extrinsic asthma, provoked 4 times each with a 1-2 wk interval, was investigated. The method was used thereafter to find the sub-threshold bronchodilating dose of a new .beta.-agonist KWD 2131 with a preferably anti-allergic property. Selection of patients and methodology of the histamine challenge procedure were carefully standardized. Histamine was administered during quiet breathing at 3 min intervals in a step-wise cumulative manner up to a point where greater than 20% decrease in FEV1.0 [forced expired volume in 1 s] was reached. The pooled intra-individual SD was 4.6% in FEV1.0, 5.0% in PEFR [peak expiratory flow rate] and 4.7% of FVC [forced vital capacity]. Pretreatment with KWD 2131, before histamine challenge, showed that the sub-threshold dose for bronchodilatation was 0.5 mg in 9 patients and 0.25 mg in 3 patients compared with 1 mg in patients with intrinsic asthma. It was important to perform individualized dose-titration of the sub-threshold bronchodilating dose of KWD 2131 before initiation of a subsequent allergen provocation study.