Influences of immobilization and footshock stress on pharmacokinetics of theophylline and caffeine in rats
Okazaki, M.; Eto, K.; Furuno, K.; Oishi, R.; Gomita, Y.
Journal of Pharmacy and Pharmacology 47(6): 530-533
1995
ISSN/ISBN: 0022-3573 PMID: 7674139 Document Number: 445029
The influences of immobilization and footshock stress on pharmacokinetics of theophylline (20 mg kg-1) and caffeine (30 mg kg-1) administered orally were examined in rats. The immobilization stress for 30 min or 1 h immediately after oral administration caused marked immobilization period-related decreases in plasma theophylline concentrations during the absorption phase, but did not affect plasma caffeine concentrations. The k-a and C-max values for theophylline were significantly decreased, and the t-max was significantly increased. On the other hand, when the immobilization stress was loaded for 1 or 3 h before the oral administration, the plasma theophylline or caffeine concentrations were not affected. The footshock stress for 30 min immediately after oral administration did not significantly decrease plasma theophylline concentrations during the absorption phase. These results suggest that the pharmacokinetics of theophylline are influenced by strong stress, possibly due to the inhibition of its absorption from the gastrointestinal tract, but the pharmacokinetics of caffeine are not influenced by stress, probably due to its central action.