as with the beta 2-adrenoceptor agonists , the onset of maximum effect with ipratropium ( about 1.5 to 2 hours ) is slower than with isoprenaline ( although significant bronchodilation usually occurs within seconds or minutes of ipratropium inhalation ) , and the duration of effect ( about 4 to 6 hours ) is longer .
C0022245
isoprenaline
C1371299
bronchodilation