Theophylline and ethylenediamine pharmacokinetics following administration of aminophylline to septic patients with multiorgan failure.

The pharmacokinetics of theophylline and ethylenediamine were examined in 6 patients with septicaemia and multiorgan failure (MOF). The patients received a bolus injection of 4 mg/kg aminophylline. Aminophylline is the ethylenediamine salt of theophylline. The clearance of theophylline was reduced in all our patients ranging from 10-66% of the value obtained in healthy volunteers. The median t 1/2 beta was 18.8 h (range 5.8-25.5) compared to a normal value of 6 h. The median clearance of ethylenediamine was 54% of the normal value, while the peripheral volume of distribution was increased to 650%. Due to this t 1/2 beta was 2.3 (2.0-2.7) h, which is 5 times the normal value of 0.55 h. There was no correlation between clearance of theophylline and ethylenediamine. As theophylline has a narrow therapeutic range, routine monitoring with measurements of serum theophylline is mandatory in patients with MOF.