Abstract
To examine the effects of serum theophylline concentration on the bronchodilating effect of beta 2-stimulant inhalated by patients with bronchial asthma, 200 micrograms-Salbutamol inhalation test was performed on 30 patients with bronchial asthma (from 17 to 71 years old, averaging 49.7; 3 mild, 15 moderate, 12 severe), who had taken theophylline at various oral doses up to 6 hours before the test. Measurements of respiratory function, serum theophylline concentration, blood pressure, pulse rate and the plasma c-AMP and c-GMP concentrations before and one hour after inhalation revealed that inhalation of 200 micrograms salbutamol significantly increased FVC, FEV1.0, PEF and plasma c-AMP (p less than 0.001). No significant change was noted in plasma c-GMP, diastolic pressure or pulse rate. Systolic pressure significantly decreased (p less than 0.05). Furthermore, no significant correlation was noted between the rates of increase (%) in FVC, FEV1.0 and PEF and those in plasma c-AMP, c-GMP and c-AMP/c-GMP in one hour after inhalation. Inaddlition no significant correlation was noted between the rates of increase in FVC, FEV1.0 and PEF one hour after inhalation and serum theophylline concentrations (0-19.3 and 0-21.5 micrograms/ml before and one hour after inhalation, respectively). The above results suggest that the bronchodilating effect of salbutamol inhalated at dose of 200 micrograms is not influenced by the serum theophylline concentration both before and at one hour after inhalation of salbutamol. The bronchodilating effect of salbutamol seems to be ascribable to an increase of intracellular c-AMP level of bronchial smooth muscle.
Published Version
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