Theophylline compounds in patients with reversible airways obstruction

Summary In a double blind cross‐over comparison of a single dose 450‐mg slow‐release aminophylline (SRA) with placebo in eleven patients with stable, reversible airways obstruction SRA produced significantly greater increase in FEV1 and vital capacity from 2 to 9 hr after administration. A second double‐blind cross‐over comparison of 450‐mg SRA with 400 mg of choline theophyllinate (CT) in eleven similar patients showed that SRA produced a slower rise in FEV1 and VC than CT. However, the increase in spirometric readings following SRA was sustained at 9 hr after administration where the spirometric recordings after CT were falling. Whereas CT produced a peak value in plasma theophylline at 1 hr, the highest values after SRA occurred at 4 or 8 hr after administration. The plasma theophylline level at 8 hr after SRA was significantly higher than that following CT. In this single‐dose study, plasma theophylline levels obtained were within the normal therapeutic range and this was not exceeded and no side effects were recorded.