It inhibits platelet aggregation by blocking the platelet P2Y12 adenosine disphosphate receptor like clopidogrel and prasugrel, but it is reversible and more rapidly acting, demanding a less convenient twice daily dosing.
Studies comparing ticagrelor and clopidogrel demonstrate a reduced risk of cardiovascular death, myocardial infarction, or stroke in acute coronary syndromes, particularly when combined with aspirin.
No dose adjustment is needed for the elderly, race, gender, body weight, smoking, renal impairment, or mild hepatic impairment; although it should not be used with more significant hepatic impairment or risk of bleeding. (It should be discontinued 5 days prior to surgery). Antifibrinolytics and/or recombinant factor VIIa may augment haemostasis.
Dyspnoea, headache, and epistaxis are the most common adverse effects; leading to discontinuation more often than for clopidogrel. It should be used with caution in patients with a history of asthma and/or COPD, or hyperuricaemia or gouty arthritis. Minor bleeding requiring medical intervention, non-coronary artery bypass graft (CABG) bleeding and ventricular pauses also occur more often, although serious adverse events are at similar rates.
Ticagrelor is a mild inhibitor of CYP3A4 and, to a lesser extent, of P-glycoprotein, so should be given cautiously with affected drugs having a narrow therapeutic window, such as ergot alkaloids. Co-administration with inhibitors of CYP3A4 may increase the exposure to ticagrelor, while inducers may reduce exposure. Ticagrelor should not be used with strong CYP3A4 inhibitors (e.g. ketoconazole, clarithromycin, nefazodone, ritonavir, and atazanavir), and cautiously with moderate inhibitors.
The benefits and risks of this, as any, drug should always be balanced by each patient’s clinical and/or laboratory profile to determine the best choice of therapy.