The effect of immobilization stress on the pharmacokinetics of omeprazole in rats.

The effects of immobilization stress on the pharmacokinetics of omeprazole were studied in rats. The immobilization stress for 30 or 60 min immediately after oral administration of the drug caused an increase in the time to reach the maximum concentration. However, such stress did not alter the area under the plasma concentration-time curve (AUC). When administered intravenously, the half-life during the elimination phase was significantly prolonged by 30 min of immobilization stress, but the AUC value remained unchanged. The intestinal propulsive activity was significantly decreased by immobilization stress. These findings suggest that immobilization stress reduces gastrointestinal motility. A resulting delay during the absorption phase of omeprazole occurs, although the degree of influence on overall pharmacokinetics is relatively insignificant.