Reliability of salivary theophylline concentration monitoring in children with bronchial asthma following the administration of different drug formulations.

The applicability and reliability of the clinical usefulness of monitoring salivary theophylline concentrations as a predictive measure of serum concentrations was evaluated in a total of 59 children with asthma, divided in four groups. Three pharmacological preparations of oral theophylline (aqueous, alcoholic and slow release) were evaluated after single administration (groups 1-3); slow release theophylline was also tested in a steady state of metabolism in children under chronic therapy with the drug (group 4). Although a good correlation between theophylline concentrations in serum and saliva was observed in each group, the wide range of variability in serum levels predicted from salivary levels (20-60%) appears to limit the usefulness of this approach. The salivary measurements of theophylline may be useful as a general guide in management of patients, or in assessment of compliance.