Ticagrelor (brand name Brilinta) is an antiplatelet medication that functions as a P2Y12 inhibitor. It works by blocking the P2Y12 receptor on the platelet surface, preventing platelets from sticking together and reducing blood clot formation. Its primary purpose is to reduce the risk of heart attack, stroke, or cardiovascular death in individuals who have experienced an acute coronary syndrome (ACS) event, such as unstable angina or myocardial infarction (MI). The medication is also used for long-term prevention against future thrombotic events, particularly following procedures like coronary stenting.
Standard Treatment Regimens
Standard treatment begins with a two-part dosing strategy to achieve rapid and sustained platelet inhibition. The first phase is the Loading Dose, typically a single 180 mg oral dose, often administered as two 90 mg tablets. This dose quickly saturates the P2Y12 receptors, achieving maximum antiplatelet effect within hours, which is necessary for stabilizing patients during an acute coronary event.
Following the loading dose, patients transition to the Maintenance Dose of 90 mg taken twice daily, approximately twelve hours apart. This regimen is usually continued for a minimum of twelve months after an acute coronary syndrome event. The fixed twelve-hour interval is important because ticagrelor’s antiplatelet effect is reversible and has a shorter duration of action compared to other P2Y12 inhibitors.
Ticagrelor is nearly always prescribed as part of a dual antiplatelet therapy (DAPT) regimen, which includes a daily maintenance dose of aspirin (75 mg to 100 mg per day). Aspirin doses higher than 100 mg daily should be avoided, as they can reduce ticagrelor’s effectiveness. For high-risk patients more than one year out from their initial event, a lower long-term maintenance dose of 60 mg twice daily may be prescribed.
Practical Administration and Management
Patients must take ticagrelor exactly as prescribed, maintaining the twice-daily schedule with an approximate twelve-hour separation between doses. The medication can be taken with or without food, as ingestion does not significantly affect absorption. Taking one dose in the morning and one in the evening helps maintain the necessary interval and improves adherence.
If a patient cannot swallow the tablets whole, they can be crushed and mixed with a small amount of water for immediate consumption. The container should be rinsed with water and the contents consumed again to ensure the entire dose is received. This mixture can also be administered through a nasogastric tube.
If a dose is missed, the patient should skip the forgotten dose and take the next dose at the regularly scheduled time. Patients should not double the dose to make up for the missed one, as this increases the risk of bleeding without providing additional benefit. Adherence is crucial due to the drug’s rapid offset of action if administration is interrupted.
Clinical Factors Affecting Dose Modification
Underlying medical conditions and drug interactions may necessitate clinical review or dose modification. Ticagrelor is metabolized primarily by the liver enzyme CYP3A4, meaning hepatic function influences the drug’s concentration. Patients with mild hepatic impairment do not require a dose adjustment. However, those with moderate liver impairment require careful consideration due to limited clinical experience.
Ticagrelor is not recommended for use in patients with severe hepatic impairment, as reduced breakdown leads to increased exposure and a higher risk of adverse effects. Conversely, renal impairment, even in severe cases or for patients on hemodialysis, does not require a dose adjustment. Although creatinine levels can sometimes rise during therapy, this is monitored closely and does not affect the drug’s efficacy or safety profile in this population.
Co-administered medications can interfere with metabolism. Strong CYP3A4 inhibitors (e.g., some antifungal or HIV medications) significantly increase ticagrelor concentration, raising the potential for side effects, including bleeding. Conversely, strong CYP3A4 inducers (e.g., rifampicin or phenytoin) speed up metabolism, leading to lower concentrations and reduced effectiveness.
Recognizing and Managing Bleeding Risk
Bleeding is the primary safety concern associated with ticagrelor use, as it inhibits platelet aggregation. This risk is inherent to all antiplatelet therapies, though the 90 mg twice-daily dose balances clot prevention and hemorrhage minimization. Bleeding events range from minor issues like bruising or nosebleeds to major events requiring medical intervention.
Patients must recognize signs of serious bleeding requiring immediate medical attention: blood in the urine, red or black stools (indicating gastrointestinal bleeding), or unexplained severe headaches (signaling potential brain bleeding). The risk of major bleeding is elevated in patients with low body weight, existing anemia, or moderate to severe chronic kidney disease.
A history of spontaneous bleeding also increases the likelihood of future hemorrhagic events. For patients requiring surgery, especially coronary artery bypass graft (CABG), ticagrelor is discontinued for at least five days prior to the procedure to mitigate excessive bleeding risk. Regular medical monitoring helps providers assess the patient’s risk profile and manage safety.