ANTIPLATELET THERAPIES IN ACS - EPCCS 09

Discussing novel antiplatelet agents — prasugrel and ticagrelor — in acute coronary syndrome, Professor Steen Kristensen (Aarhus, Denmark) said it is now apparent that some patients have a low response to the widely used clopidogrel. This appears to be related to poor metabolism of the prodrug.

Two newer antiplatelet drugs, prasugrel and ticagrelor, act in way as clopidogrel as inhibitors of the platelet P2Y12 receptor.

Prasugrel (also a prodrug) is more potent than clopidogrel, and it has a more uniform response and faster onset. It is marketed for ACS patients undergoing percutaneous coronary intervention. In the TRITON-TIMI 38 trial, prasugrel was shown to have greater efficacy than clopidogrel. However, there was an increased risk of bleeding in certain groups. “Patients with prior stroke or TIA should not use the drug, and we should probably use a reduced dose in patients aged over 75 or with low bodyweight.”

All three drugs act as inhibitors of the platelet P2Y12 receptor. Unlike clopidogrel and prasugrel, ticagrelor is a reversible platelet inhibitor. This might be an advantage in some circumstances but could also be a problem. “The challenge in the real world will be compliance. Patients have to take this drug twice daily and if they stop taking it after a day they will be unprotected.” In the PLATO trial, which was reported at ESC, ticagrelor was more effective than clopidogrel, with no difference in bleeding.

Ticagrelor is not yet licensed.
Back to the overview page...