[Serum levels and bronchodilatation after intravenous administration of theophylline in asthmatic patients].

Forced expiratory volume in the first second (FEV1) and serum theophylline levels were measured comparatively in 26 patients with stable bronchial asthma after a 240 mg theophylline infusion. The mean (+/- s.e.m.) elimination half-life and clearance of theophylline were 6.37 +/- 2.03 hours and 0.78 +/- 0.31 ml/min/kg respectively. A bronchodilator response (more than 20% increase in FEV1) was obtained in 17 patients whose pretreatment FEV1 was less than 30% of predicted normal values. No significant bronchodilator response was obtained in the other patients. There was no relationship in responders between changes in FEV1 and simultaneous serum theophylline levels. Maximal ventilatory response was apparent 1 to 2 hours only after the theophylline peak concentration.