• The serum-saliva theophylline level ratio was measured in 19 chronically asthmatic children after their conditions were stabilized on a sustained-release theophylline preparation. Simultaneous serum and saliva samples were collected at 0, 4, 6, and 10 hours after theophylline dose and measured by high-pressure liquid chromatography. The mean ratio for the group of 1.52 ± 0.64 approximated the mean ratio from previous reports. However, the correlation coefficient (r =.80) was lower, and the interpatient and intra-patient variability (25% and 23%) much higher, than in previous reports. The possible mechanism of these findings in relation to sustained-release preparations are discussed. These data question the use of salivary theophylline determinations to monitor therapy. Dosage should be based on serum measurements.
(Am J Dis Child 1981;135:137-139)
Kelly HW, Hadley WM, Murphy SA, Skipper BG. Monitoring Children on Sustained-Release Therapy by Salivary Theophylline Levels. Am J Dis Child. 1981;135(2):137-139. doi:10.1001/archpedi.1981.02130260029009