In vitro antiaggregant activity of paracetamol and derivatives.

The in vitro antiaggregating action of paracetamol and ten of its derivatives was studied by observing their action on collagen, adenosine-5 diphosphate (ADP) and arachidonic acid-induced platelet aggregation. It is established that in vitro activity appears not only with paracetamol but also with its positional isomers and its isosteric derivatives; this involves the replacement of oxygen by sulfur and that of the NH group of oxygen. Paracetamol and its derivatives also have an inhibiting effect on the serotonin release and the thromboxane synthesis of collagen-stimulated platelets.