Introduction. Acute postoperative pain continues to be a dilemma to patients and clinicians.Aim. To define the efficacy, tolerability and pharmacokinetics of paracetamol and ketoprofen in patients after the abdominal aortic surgery. Setting and design in University hospital – intensive therapy unit (clinical part), clinical pharmacy and biopharmacy unit (biochemical part), and pharmaceutical company (statistical part). Prospective randomized study.Material and Methods. 40 adult patients (50–84 years) undergoing abdominal aortic surgery were randomized equally into two groups. After extubation the patients in group 1 (G1) were administered a 1 g paracetamol infusion, and in group 2 (G2) – a 100 mg ketoprofen infusion, both within 15 minutes. All the patients received an epidural infusion of bupivacaine with fentanyl. The following parameters were recorded: mean arterial pressure (MAP), heart rate (HR), central venous pressure (CVP), plasma concentration of paracetamol and ketoprofen. Postoperative pain was assessed with the visual analogue scale (VAS).Results. The mean values of the MAP, HR and CVP were within normal limits in the both groups. No significant differences were noticed in the assessment of postoperative pain and total use of an opioid. The mean therapeutic plasma concentration of paracetamol and ketoprofen remained up to 180 minutes and up to 120 minutes, respecively.Conclusions. The study enabled us to conclude that intravenous paracetamol as well as ketoprofen have good effectiveness and tolerability. There is no need to modify dosage of these drugs to elderly patients. After paracetamol infusion the therapeutic plasma concentration remains longer than after the ketoprofen infusion.