Antiplatelet Therapy with Ticagrelor

Mechanism of Action

The American College of Chest Physicians recommends ticagrelor as a direct inhibitor of the P2Y12 receptor, which belongs to the cyclopentyl-triazolopyrimidine class, acting as an antiplatelet agent that works by inhibiting platelet aggregation through reversible binding to the P2Y12 receptor 1
Ticagrelor specifically targets platelets rather than affecting the coagulation cascade, unlike traditional anticoagulants, and binds to the receptor at a location distinct from the ADP binding site and blocks ADP-mediated receptor activation in a noncompetitive fashion, likely through an allosteric mechanism 2
The European Society of Cardiology notes that ticagrelor does not require hepatic conversion to an active metabolite, allowing for more rapid onset of action, unlike thienopyridines, such as clopidogrel and prasugrel 1

The American Heart Association states that ticagrelor achieves inhibition of ADP-induced platelet aggregation within 30 minutes, exceeding that obtained with loading doses of clopidogrel, with a peak inhibitory effect seen about 2 hours after a loading dose of 180 mg or a maintenance dose of 90 mg twice daily 1
Ticagrelor provides more rapid and potent inhibition of platelet aggregation compared to clopidogrel, according to the American College of Cardiology, with a reversible binding mechanism, allowing for faster recovery of platelet function, with a half-life of approximately 12 hours 2, 3

The American College of Cardiology recommends ticagrelor for prevention of atherothrombotic events in adults with acute coronary syndromes, including those managed medically or with percutaneous coronary intervention or CABG, with a reduced composite endpoint of cardiovascular death, MI, or stroke compared to clopidogrel, as demonstrated in the PLATO trial 1, 3
The European Society of Cardiology notes that ticagrelor also demonstrated lower rates of myocardial infarction and cardiovascular mortality compared to clopidogrel, in patients with unstable angina, STEMI, or NSTEMI 1

The American Heart Association states that ticagrelor's bleeding profile is different from traditional anticoagulants, increasing the risk of non-procedure related bleeding rather than affecting the entire coagulation system, with side effects including dyspnea, which occurs in up to 15% of patients, and bradycardia with ventricular pauses 1, 3, 4
The American College of Chest Physicians recommends that ticagrelor should be discontinued at least 5 days before surgery, and in cases of severe bleeding, platelet transfusion may be less effective than with thienopyridines due to ticagrelor's mechanism of action 5, 6