Controlled study of the bronchoconstriction effect of pindolol administered intravenously or orally to patients with unstable asthma.

Pindolol, a beta-blocking drug, was given intravenously (0.2 mg) to 4 patients and orally (15 mg) to 4 patients, all in remission after acute exacerbation of asthma. In all cases it induced chest tightness and marked decrease in specific airway conductance, FEV1 and FVC and maximum expiratory flow at low lung volumes. The increase in airway obstruction after pindolol was not reversed by inhalation of a beta-sympathomimetic aerosol. The results suggest that conventional doses of pindolol may cause significant worsening of asthma in patients with unstable disease.