Comparative study on the effects of acetylsalicylic acid, indomethacin and paracetamol on metabolites of arachidonic acid in plasma, serum and urine in man.

The effects of acetylsalicylic acid, indomethacin and paracetamol on the plasma and serum levels and the urinary excretion of arachidonic acid metabolites in man were demonstrated. The inhibition of prostaglandin synthesis was reflected better in the urinary excretions than in the plasma levels of arachidonic acid metabolites. A clear-cut reduction by acetylsalicylic acid and indomethacin in serum T X B2 can be reached within 24 h. Paracetamol had no uniform influence on the prostaglandins studied. The values returned to the initial level in seven days after indomethacin and in two weeks after acetylsalicylic acid treatment. In some cases a rebound overshoot in prostaglandin concentrations was observed after the discontinuation of the treatment.