Saliva and Serum Theophylline Concentration in Management of Asthma in Children on Sustained-Release Therapy

Abstract

Relationships between theophylline concentrations in saliva and serum and lung functions were investigated in 27 asthmatic children receiving a sustained-release theophylline. Improvements in lung functions were related to increasing theophylline concentrations. The concentration required to maintain normal lung functions was 10 μg/ml in serum and 7 μg/ml in saliva. Theophylline concentrations in serum and saliva statistically correlated (r - 0.949). The mean serum-saliva ratio was 1.45 ′0.02, with a 13.7% intersubject and a 14.9% intrasub-ject variation. Predicted serum concentrations were ′2 μtg/ml of measured concentrations in 92 samples (92%). From the results, theophylline concentrations in saliva may be useful in predicting serum values.