What is the recommended dosage and duration of ticagrelor (a P2Y12 inhibitor) in patients with acute coronary syndrome (ACS)?

Ticagrelor Dosage and Duration in Acute Coronary Syndrome

For patients with acute coronary syndrome (ACS), ticagrelor should be administered at a loading dose of 180 mg followed by 90 mg twice daily for 12 months, in combination with low-dose aspirin (75-100 mg daily). This recommendation is based on current guidelines from both European and American cardiology societies 1, 2.

Dosing Regimen

Initial Treatment

• Loading dose: 180 mg orally as a single dose
• Maintenance dose: 90 mg twice daily
• Concurrent aspirin: 75-100 mg daily (specifically 81 mg daily recommended with ticagrelor)

Duration of Therapy

• Standard duration: 12 months for all ACS patients, regardless of whether they received medical management or underwent stent placement 1, 2
• Extended therapy: For selected patients at high ischemic risk and low bleeding risk, extended therapy beyond 12 months may be considered, potentially with a reduced dose of 60 mg twice daily 2
• Shortened therapy: For patients at high bleeding risk (e.g., PRECISE-DAPT score ≥25), discontinuation after 6 months may be considered 1

Comparison with Other P2Y12 Inhibitors

Ticagrelor is recommended in preference to clopidogrel for ACS patients 1:

• Ticagrelor can be administered regardless of prior P2Y12 inhibitor treatment
• Ticagrelor has a faster onset of action and provides greater inhibition of platelet aggregation than clopidogrel 3
• Clopidogrel (600 mg loading dose, 75 mg daily maintenance) should only be used when ticagrelor or prasugrel are not available or are contraindicated 1

Special Considerations

Pre-treatment Approach

• For patients with NSTE-ACS undergoing invasive management, ticagrelor administration (180 mg loading dose, 90 mg twice daily) should be considered as soon as the diagnosis is established 1

Bleeding Risk Management

• Recent evidence suggests that discontinuing aspirin after 1-3 months while continuing ticagrelor monotherapy may reduce bleeding risk without increasing ischemic events 4, 5, 6
• The TICO trial showed that switching to ticagrelor monotherapy after 3 months of DAPT reduced net adverse clinical events compared with 12-month DAPT (3.9% vs 5.9%, HR 0.66) 4
• The ULTIMATE-DAPT trial demonstrated that ticagrelor monotherapy from month 1 to month 12 after PCI reduced clinically relevant bleeding compared to ticagrelor plus aspirin (2.1% vs 4.6%, HR 0.45) without increasing ischemic events 5

Common Pitfalls and Caveats

1. Premature discontinuation risk: Early stopping of ticagrelor increases the risk of stent thrombosis, myocardial infarction, and death 2
2. Bleeding risk: Monitor for bleeding complications, especially in patients with risk factors (age ≥65, low body weight, diabetes, prior bleeding, concomitant anticoagulants) 7
3. Dyspnea: Ticagrelor can cause dyspnea (usually mild to moderate), which should not be confused with heart failure or pulmonary conditions 2, 3
4. Medication interactions: Consider potential drug interactions, especially with strong CYP3A4 inhibitors/inducers
5. Surgery timing: If non-urgent surgery is needed, ticagrelor should be discontinued ≥5 days before the procedure 2

Algorithm for Duration Modification

1. Standard approach: 12 months of ticagrelor 90 mg twice daily + aspirin 75-100 mg daily
2. If high bleeding risk (PRECISE-DAPT ≥25):
   • Consider shortening duration to 6 months
   • OR consider switching to ticagrelor monotherapy after 1-3 months
3. If high ischemic risk and low bleeding risk:
   • Consider extending beyond 12 months
   • Consider reduced dose (60 mg twice daily) for extended therapy

By following these evidence-based recommendations, clinicians can optimize the balance between preventing ischemic events and minimizing bleeding risk in ACS patients.