A comparison of the bronchodilator effects of broxaterol and salbutamol

In 12 adult patients with reversible bronchospasm (7 bronchial asthma and 5 chronic obstructive bronchitis) the bronchodilator activity and tolerability of 200 and 400 mcg of broxaterol hydrochloride (Z 1170) were compared to those of 200 mcg of salbutamol administered by metered-dose inhaler. A single dose of the drugs was compared in a double-blind balanced latin square cross-over design. FEV1, FVC, MMEF, MEF25, heart rate and blood pressure were measured just before and 7.5, 15, 30, 60, 120, 180 and 240 min after each treatment. At these times clinical evaluation was also carried out to ascertain the presence of side effects. In the doses employed, broxaterol and salbutamol caused significant increases over baseline FEV1, MMEF and MEF25 from 7.5 to 240 min and FVC from 7.5 to 120 min. The difference between the effects of the two doses of broxaterol on FVC, MMEF and MEF25 was significant at 15 min. No significant difference was observed in the activity curves of 400 mcg of broxaterol and salbutamol. The effects of salbutamol were significantly greater than those of 200 mcg of broxaterol on FEV1 at 7.5 and 15 min and on FVC, MMEF and MEF25 at 15 min. All three treatments were well tolerated. No significant changes were observed in heart rate or blood pressure and tremors were not reported in any patient.