The use of theophylline clearance in pediatric status asthmaticus. I. Interpatient and intrapatient theophylline clearance variability.

A group of 167 pediatric asthmatics were followed up over four years, and their theophylline clearance values were recorded when they were admitted for status asthmaticus. A slow and gradual decrease of the clearance value was noted in all age groups. The clearance did not change significantly between the ages of 2 and 9 years. Longitudinal intrapatient clearance changes achieved statistical significance after the age of 9 years. When the patient groups were studied according to their initial clearance values, it became evident that only the patients with clearance values of 80 mL/kg/h showed significant changes of this value. In our patient group, obesity did not play a significant role in effecting a change in theophylline clearance.