The effect of sympathicomimetics and anticholinergics on antigen-induced airway obstruction

The prophylactic and therapeutic effects of a sympathicomimetic drug 1-(3,5-dihydroxy-phenyl)-2-([1-(4-hydroxy-benzyl)-ethyl]-amino)-ethanol-hydrobromide (fenoterol HBr, Berotec) and an anticholinergic drug (8r)-8-isorpopyl-3 alpha-[(+/-)-tropoyl-oxy]-1 alpha H,5 alpha H-tropanium-bromide (ipratropium bromide, Atrovent) were tested on a series of 13 boxer dogs, exposed to allergen challenge. The therapeutic and prophylactic influence showed to be similar for both substances. The effect on bronchoconstriction was not followed by a similar influence on arterial blood gas values. The administration of the two drugs during prolonged airway obstruction induced by a continuous exposure to allergen showed no influence on this kind of airway obstruction. Various mechanisms must be assumed in this prolonged airway obstruction when compared to acute obstruction after short exposure to allergen.