[The effect of (8r)-3alpha-hydroxy-8-isopropyl-1alphaH,5alphaH-tropaniumbromide-(+/-)-tropate ((ipratropiumbromide) on tracheobronchial spasm, bronchial and salivary secretions, ECG and heart rate (author's transl)].

At very low doses (8r)-3alpha-hydroxy-8-isopropyl-1alphaH,5alphaH-tropaniumbromide-(+/-)-tropate (ipratropiumbromide, Sch 1000, Atrovent) and atropine inhibit acetylcholine-induced bronchospasms in guinea-pigs and dogs. The dose ratio main effect vs. most sensitive side effect (inhibition of saliva secretion) is 1:10 for i.v. injection and 1:100 for aerosol application. When both compounds are administered in a nebulized form bronchodilatation occurs immediately. The maximum effect of Sch 1000 occurs somewhat later than that of atropine but the duration of action is much longer. Bronchial secretion in guinea-pigs is increased by small doses of Sch 1000 and atropine. These doses correspond to bronchodilating doses.