A comparative study on the ventilatory and haemodynamic effects of xamoterol and atenolol in asthmatic patients

The effects of single oral doses of atenolol 50 mg and xamoterol 200 mg (a recently developed partial beta 1-adrenoceptor agonist) on lung function, heart rate and blood pressure were investigated in 11 patients with asthma. Xamoterol caused a significant increase in heart rate and systolic blood pressure, which changes are consistent with the partial beta 1-adrenoceptor agonist activity of this drug. Atenolol induced a significant decrease in FEV1 and the forced vital capacity (FVC); there was a non-significant change in FEV1 and FVC after xamoterol. There was no significant difference between the effects of atenolol and xamoterol of FEV1 and FVC. Bronchospasm induced by atenolol 50 mg and xamoterol 200 mg was completely reversed by inhalation of the beta 2-adrenoceptor agonist terbutaline to a cumulative dose of 4.0 mg.