| Abstract: | A direct relationship between bronchodilator efficacy and toxicity by the measurement of serum theophylline concentrations is well established. This study evaluated, in children receiving either 12-hour (Theo-Dur) or an experimental 24-hour (Theo-Beads) preparation, the most common time to reach peak and trough levels in the serum. Twenty-three children with chronic asthma between the ages of 7 and 12 years participated in the study. Twelve received theophylline every 12 hours at a dose ranging from 400 to 800 mg per 24 hours. Eleven children received a 24-hour preparation at a dose ranging between 400 and 1000 mg per 24 hours. The results demonstrated no relationship between dosing interval and the appearance of peak or trough levels with Theo-Dur. Theo-Beads reached its peak in 9 to 11 children between six and eight hours and for 10 to 11 children the trough value was at the end of the dosing interval. |
