Ticagrelor is a medication used to treat cardiovascular diseases, particularly in antiplatelet therapy following myocardial infarction (heart attack). It helps prevent thrombus formation by inhibiting platelet aggregation, thereby reducing the risk of recurrence. Here’s a detailed explanation of its mechanism and duration of action.

1. Mechanism of Action of Ticagrelor
   Ticagrelor belongs to a class of drugs known as P2Y12 receptor antagonists. Unlike similar drugs such as Clopidogrel, it directly inhibits the P2Y12 receptor, blocking the action of ADP (adenosine diphosphate), which activates platelets. This reduces platelet activation and aggregation, thereby decreasing thrombus formation.

2. Half-Life
   The half-life of Ticagrelor is approximately 7 to 12 hours. The half-life refers to the time required for the plasma concentration of the drug to decrease to half its initial concentration. Therefore, Ticagrelor needs to be administered periodically to maintain plasma concentrations within the therapeutic range, ensuring its effectiveness.

3. Dosage Frequency and Recommendations
   It is generally recommended that patients post-myocardial infarction use Ticagrelor for long-term antiplatelet therapy, typically at a dosage of one tablet (90 mg) taken twice daily. This frequency helps sustain the platelet inhibition effect and reduces the risk of recurrent cardiovascular events.

4. Precautions
   Although Ticagrelor is effective in preventing cardiovascular events, attention should be paid to potential side effects and contraindications. For instance, some patients may be allergic to the drug or have a tendency to bleed, necessitating careful evaluation and management under medical guidance.

In summary, Ticagrelor, as an important antiplatelet medication, has its efficacy influenced by its half-life, with a recommended dosing frequency of twice daily to maintain therapeutic effects. Patients should strictly follow medical advice and undergo regular check-ups to ensure the drug's safety and effectiveness.