EFFECT OF SULPHINPYRAZONE AND OTHER DRUGS ON THE PLATELET RESPONSE DURING THE ACUTE PHASE OF THE ACTIVE ARTHUS REACTION IN GUINEA-PIGS

It has been shown that a systemic platelet response follows the induction of the active Arthus reaction in guinea-pigs. This response was quantified by measurement of the transiet fall in circulating platelet count and by measurement of the sequestration of platelets, partially as aggregates, in the vascular beds of the lungs and liver. Administration of inhibitors of the platelet secretion reaction, sulphinpyrazone, phenylbutazone, aspirin and indomethacin resulted in partial inhibition of the thrombocytopenia. Two metabolites of sulphinpyrazone, the sulphoxide (G 31442) and the p-hydroxy derivative (G 32642) were tested and of the two the sulphoxide was slightly more potent than the parent compound. © 1979.