The effect of intravenous theophylline on the outcome of inhospital treatment of acute bronchospasm has been assessed, comparing the results achieved by computer-assisted dosing, designed to achieve and maintain a serum theophylline level of 16 μg · ml−1 (10 patients) with those of unaided physicians (15 control patients). The outcome measures compared were clinical improvement, peak expiratory flow rate and serum theophylline concentration.
Loading doses of theophylline in the control and computer groups were: 167 and 437 mg, respectively. Initial serum theophylline concentrations, measured 20 min after the loading dose, were 13.6 and 17.0 μg · ml−1 in the control and computer groups, respectively. In patients who had not received theophylline prior to admission, loading doses and initial concentrations were: 200 mg and 9.4 μg · ml−1 in the control group (n = 5) versus 613 mg and 15.7 μg · ml−1 in the computer group (n = 4), respectively.
During maintenance therapy, serum theophylline concentrations were kept in the therapeutic range (10–20 μg · ml−1) throughout 51 % and 77 % of the hospitalisation period, in the control and computer groups, respectively. There were no differences between the two groups in the rate or extent of clinical improvement or in change in peak expiratory flow rate.
The computer assisted theophylline dosing regimen outperformed that of the unaided physicians in achieving and maintaining therapeutic serum theophylline concentrations in acute bronchospasm. There was no correlation between clinical outcome and serum theophylline concentration, but this may have been due to the small sample size and modest difference in serum theophylline between the two groups. The findings serve as an additional argument in favour of the trend away from reliance on theophylline as first line therapy in acute bronchospasm.