Table 1: Effect of anticholinergics on airways hyperresponsiveness in asthmaa.


Beta blockersAbolished response
Bradykinin5-fold increase in PD35
Capsaicin60% reduction in response
Distilled water50–100% reduction in response
Exercise30% reduction in response
Histamine10-fold increase in PC100 SRaw
HyperpneaAbolished response in children
Prostaglandin D212- to 22-fold increase in PC20
Psychogenic stimulationAbolished response
Reflux or esophageal acidificationAbolished response
Thromboxane A223-fold increase in PC20

aAnticholinergics used were either ipratropium bromide or atropine delivered via aerosol. Results reviewed in detail elsewhere [35]. Abbreviations: PC20 and PD35: provocative concentration (or dose) of agonist producing a 20% or 35% decrease, respectively, in forced expiratory volume in 1 sec (FEV1); PC100 SRaw: provocative concentration of agonist producing a 100% increase in specific airways resistance.