Theophylline serum concentration and therapeutic effect in severe acute bronchial obstruction: the optimal use of intravenously administered aminophylline.

In 20 patients with acute exacerbation of bronchial obstruction, the therapeutic effect of high (20 mg/L) and low (10 mg/L) serum concentrations of theophylline was compared in a double-blind randomized study. The theophylline dose, administered as a continuous aminophylline infusion, was individually adjusted by means of repeated measurements of serum concentrations. At 28 h after starting therapy the high concentration group showed a significantly greater improvement in pulmonary function as assessed by FEV1 (0.57 +/- 0.52 L (mean +/- SD) versus 0.1 +/- 0.18 L, p less than 0.01) and FVC (1.0 +/- 0.65 L versus 0.01 +/- 0.66 L, p less than 0.02). As a measure of the overall clinical improvement, the time during which intravenous therapy was required was also shorter in the high-dose group (61.7 +/- 25.8 h (mean +/- SD) versus 116 +/- 49.7 h, p less than 0.02). The occurrence of side effects in the two groups was not significantly different. In patients with severe acute bronchial obstruction, serum theophylline concentrations around 20 mg/L seemed to offer a definite therapeutic advantage, thus, routine serum concentration measurements and the use of accurate infusion devices for optimal dose adjustment may be justified.