Does stress influence ampicillin concentration in serum and tissues?

Exercise produces changes of drug levels in plasma and increases the concentration of free fatty acids (FFAs), which may interfere with drug-protein binding. FFAs seem to play an antagonistic role to drugs since they have a strong binding capacity to serum albumin. The aim of this study was to evaluate the influence of the consecutive exercise-induced stress in ampicillin levels. Two groups of Wistar rats were used. Group A consisted of six subgroups that were subjected to cold swimming (4 degrees C) for 5, 10, 15, 20,25, 30 days respectively. Group B was the control group. The animals were injected im. with ampicillin (1 g/Kg/8h in 5 doses). Results showed that exercise enhanced stress parameters (FFAs, adrenal weight, Ht%) and led to an ampicillin increase in all experimental groups comparatively to controls.