Inhibition of thrombocytopenic episodes caused by the Arthus reaction, the sub-lethal Forssman reaction and ADP.

Through the use of 51Cr-labelling about 50% of circulating platelets were shown to be permanently removed from the circulation subsequent to the Arthus reaction but not after the sub-lethal Forssman reaction or the repeated injection of ADP to guinea pigs. Oral administration of ticlopidine inhibited the transient thrombocytopenia caused by ADP. Cyclooxygenase inhibitors including sulphinpyrazone and its thioether metabolite inhibited the thrombocytopenia of the Arthus reaction but only sulphinpyrazone effectively inhibited the thrombocytopenia of the sub-lethal Forssman reaction.