Monitoring children on sustained-release therapy by salivary theophylline levels
H. W. Kelly, W. M. Hadley, S. A. Murphy and B. G. Skipper
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 intrapatient 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.
