The pharmacodynamics of theophylline (euphylline)

: A single intravenous administration of 2.4%-10.0 euphylline to 35 patients with obstructive affections of the lungs entailed a broncholytic effect in large airways in patients with reversible obstruction under sub-therapeutical theophylline concentrations in the serum. In patients with mixed type of the obstruction and restrictive disturbances ineffective ventilation got worse, ventilation-perfusion relations disagreed, hemoglobin affinity to oxygen grew, pulmonary artery pressure dropped against the signs of pulmonary hypertension, EEG changed according to asynchronism pattern corresponding to brain hyperactivity. There was also elevation of both norepinephrine and epinephrine serum levels due to slow parenchymatous hepatic circulation which inhibited clearance of the substances. There was no relationship between changes in the indices and theophylline concentrations in the range 3.8-8.8 micrograms/ml.