Salivary theophylline monitoring in asthmatic children

Abstract

The usefulness of determination of salivary concentrations of theophylline for estimation of the serum concentration of the drug was tested in asthmatic children receiving daily 15-20 mg/kg of aminophylline. Theophylline was measured in saliva samples obtained after stimulation with citric acid and bromhexine, and in the blood serum, and the ratio of saliva: serum theophylline concentrations was calculated. The correlation between saliva and serum theophylline concentration was better for saliva samples obtained after bromhexine stimulation (r = 0.9496) than after citric acid stimulation (r = 0.8506). Using the mean value of the saliva: tissue theophylline concentration ratio of 0.6795, the serum theophylline concentration may be satisfactorily predicted (r = 0.9810). The stimulation of salivation with bromhexine is more suitable for the Abbott TDX Drug Monitoring System than the stimulation with citric acid, and the method is suitable for a routine monitoring of theophylline concentrations in the course of theophylline therapy.