Antiplatelet strategy: a brief historical review

The first three drugs tested in clinical trials for their potential antiplatelet effects were all already used in current practice for different reasons, unrelated to thrombosis and ischemic artery disease.

Aspirin was known as an anti-inflammatory compound, sulfinpyrazone was used for its uricosuric properties and dipyridamole was endowed with vasodilatory (coronarodilatory) effect. Their mechanism of action, as antiplatelet agents, was largely unknown, but the possibility of replacing oral anticoagulants with relatively safer substances, not requiring any laboratory control, convinced many clinicians to adapt an antiplatelet strategy, even before the results of well-planned and conducted clinical trials were made available.

The discovery of the crucial role of prostaglandins and thromboxane A2 (TxA2) in platelet function and of their possibly unselective pharmacological control by aspirin, stimulated for the first time the search for a more rational antiplatelet strategy.

However, the development of selective TxA2-synthase inhibitors, TxA2-receptor antagonists and of compounds endowed with both properties was not followed by the expected clinical results. This was due to several reasons, including the complex re-orientation of platelet arachidonate metabolism following pharmacological suppression of TxA2 synthesis or of its receptor function.