Abstract
One hundred and sixty nine asthmatic children, 117 boys and 52 girls with mean age of 8 years 11 months, were given 16 to 19mg/kg/day of a sustained-release theophylline(Theo-Dur), and were divided into two groups, 68 with every 12-hour (b. i. d.) and 101 with every 8-hour (t. i. d.) dosage regimen. At the end of 4 days on these dosage, the serum theophylline concentrations were measured by the enzyme immunoassay.
The younger children less than 8 years of age had 4-hour postdose levels of 14.1±4.9μg/ml (b. i. d.), 11.8±3.6μg/ml (t. i. d.) and older children over 9 years of age having 15.5±6.3 (b. i. d.) and 14.0±4.6 (t. i. d.) respectively. There were significant positive correlations between dosage and serum levels among different age and dosage groups.
Therapeutic level of 10 to 20μg/ml was observed more often in t. i. d. than b. i. d. regimen, and the level of over 20μg/ml and single case of nausea and vomiting seen in b. i. d. group.
In conclusion, even sustained-release theophylline preparation can be given every 8-hour to asthmatic children who do not respond to 12-hour dosage regimen clinically with fluctuation of the serum level. Suggested schedule based on the serum concentration followed.
Age Dosage/12-hour 8-hour
Less than 8 years 6-7mg/kg/dose 4-5mg/kg/dose
Over 9 years 5-6 3-4
