Interindividual changes in theophylline pharmacokynetics in acute asthmatic children: theophylline dosage predicition

Using fluorescence polarization immunoassay, theophylline serum concentration and theophylline pharmacokinetics after a single iv infusion of theophylline were determined in children (n=30), aged 1-10y with severe bronchoobstruction. Pharmacokinetic constants and therapy simulation were calculated on an M 24 Olivetti personal Computer. A dose of 5 mg pf theophylline (Aminophylline, Lek)per kg body mass resulted in therapeutic concentration in only six children, 45 minutes after the end of infusion. In five children, it persisted after 60 minutes, but after 300 minutes therapeutic therapeutic concentration was present in one child only. According to the results of theophylline therapy simulation in acute bronchoobstruction, optimal theophylline serum concentration should be achieved by a continuous iv infusion of 2 +/- 1 mg/kg/h. Interindividual differences in theophylline pharmacokinetics necessitate serum theophylline measurement and individual dosing.