Comparison of the pharmacokinetics of paracetamol from two generic products in patients after total gastric resection

Gastrectomy leads to pathophysiological changes within the alimentary tract, which may affect drug absorption and pharmacokinetic parameters (PK). The need to apply orally administered analgesics in this group of patients is often related with alternative application of currently available generic products. Thus, from the clinical point of view it is necessary to evaluate the PK of these drugs to confirm their equivalence. The aim of the study was therefore an analysis of the pharmacokinetics of paracetamol from two generic products in patients after total gastric resection. The research was carried out on two groups of patients after gastrectomy with Roux-en-Y reconstruction (n=30; mean [SD] age, 63.0 [11.5] years; weight, 67.6 [13.7] kg; and height, 166.4 [9.1] cm). The patients received paracetamol in a single orally administered dose of 1,000mg. Blood samples were collected within 6h of drug administration. The concentration of paracetamol and paracetamol glucuronide in the blood plasma was marked by means of a validated high-pressure liquid chromatography with ultraviolet detection (HPLC-UV). The main PK for paracetamol in group 1 (n=17) and 2 (n=13) were as follows: Cmax, 9.46 (3.66) and 12.79 (5.32)µg/ml, respectively (p=0.0517); AUMC0-t, 77.64 (30.37) and 51.01 (15.76)µg h2/ml (p=0.0046); AUC0-inf, 41.61 (23.52) and 30.28 (9.74)µg h/ml (p=0.0862); tmax, 1.68 (0.63) and 0.50 (0.25)h (p