EN
The aim of the study was to investigate the effects of age on the pharmacokinetics of paracetamol (as a model drug) in calves. The experiment was carried out on 15 healthy BW (Black-and-White) breed calves. Paracetamol (5 mg/kg bw.) was administered per os on day ten, fourteen and twenty of the calves' lives. The concentration of a model drug in plasma was determined by the spectrophotometer method. Pharmacokinetic parameters were estimated through a non-compartmental method, using the TopFit computer program. The obtained results indicate that the age of calves significantly influenced the pharmacokinetic parameters of paracetamol. A significant increase in the maximum concentration of the drug was noted, as well as in the volume of distribution and metabolic clearance. A significant decrease in mean residence time, biological half-life and area under curve was also observed. The results obtained in the study suggest that the activity of enzymes involved in the metabolism of paracetamol increases with the age of calves. It was therefore concluded that age should obviously be taken into account when studying drug metabolism in calves