• Simultaneous saliva and plasma theophylline levels in 12 chronic asthmatic children were measured by high pressure liquid chromatography following administration of a theophylline preparation. In five subjects, simultaneous plasma and salivary theophylline were measured one week later. A strongly positive correlation between plasma and salivary theophylline levels was found at all time periods tested. There was no substantial difference in the plasma-saliva theophylline ratio determined one week later. A predicted plasma level was compared with the observed value. The proportionality of predicted to observed plasma theophylline levels using either the entire study group mean plasma-saliva ratio or each individual's ratio was approximately 1.00 with 9% variability. When a previously reported plasma-saliva theophylline ratio was used for comparison, the predicted plasma theophylline was 15% above the observed plasma level.
(Am J Dis Child 131:970-972, 1977)
Galant SP, Gillman SA, Cummins LH, Kozak PP, Orcutt JJ. Reliability of Salivary Theophylline as a Guide to Plasma Theophylline Levels. Am J Dis Child. 1977;131(9):970-972. doi:10.1001/archpedi.1977.02120220036004