Benazepril, an angiotensin converting enzyme inhibitor: drug interaction with salbutamol and bronchial response to histamine in normal subjects

Aims To investigate the effect of the angiotensin converting enzyme inhibitor, benazepril, on pulmonary function.
Methods We investigated the influence of benazepril, on lung function and the interaction with inhaled salbutamol (0.1 to 6.6  mg) and histamine (0.03 to 30.69  g  l^?1 ) in normal subjects. Benazepril 20  mg, salbutamol 8  mg, propranolol 160  mg, and placebo were given orally once daily over 10 days.
Results On day 8, there was no difference in the area under the salbutamol dose-response curves between benazepril, placebo and oral salbutamol ( P >0.05), propranolol shifted the curves to the right ( P <0.05). On day 10, histamine challenge resulted in following P D ₃₅sGaw values (geometric mean and 95% CI): with placebo 1.02 (0.95–1.09)  g  l^?1 , benazepril 1.04 (0.99–1.08), salbutamol 1.19 (1.13–1.25), propranolol 0.57 (0.50–0.65).
Conclusions Benazepril had no influence on baseline lung function, caused no interaction with inhaled salbutamol and the bronchial response to histamine was similar to placebo. However, our findings in normal subjects cannot be extrapolated automatically to asthmatics.