Ticagrelor: A Modern Antiplatelet in Acute Coronary Syndrome (ACS)

Ticagrelor: Mechanism, Uses, Contraindications & Key Clinical Pearls

Ticagrelor is a potent, reversible P2Y12 receptor inhibitor widely used in acute coronary syndrome (ACS) to prevent thrombotic complications. Compared with clopidogrel, it offers faster onset, stronger platelet inhibition, and improved cardiovascular outcomes, making it a preferred agent in many ACS protocols.

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How Ticagrelor Works

Ticagrelor blocks the P2Y12 receptor on platelets, preventing ADP-mediated platelet activation.

This results in:

Rapid onset of antiplatelet action

More consistent platelet inhibition

Reduced risk of stent thrombosis

Improved mortality in ACS (as shown in the PLATO trial)

Unlike clopidogrel, ticagrelor is not a prodrug, so its action is not dependent on liver enzyme activation.

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Indications

Ticagrelor is commonly used in:

✔ Acute Coronary Syndrome

STEMI (with or without PCI)

NSTEMI

Unstable angina

Usually combined with low-dose aspirin (dual antiplatelet therapy).

✔ Post-PCI Antiplatelet Strategy

To reduce risk of:

Stent thrombosis

Recurrent MI

Stroke

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Dosage

Loading dose: 180 mg once

Maintenance: 90 mg twice daily for 12 months in ACS

May reduce to 60 mg twice daily for long-term secondary prevention

Always used with aspirin 75–100 mg/day.

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Contraindications

Ticagrelor should NOT be used in the following situations:

1. Active bleeding

2. History of hemorrhagic stroke

3. Severe hepatic impairment

4. Allergy or hypersensitivity

5. Concomitant use of strong anticoagulants or fibrinolytics

6. High-dose aspirin (>100–150 mg daily)

7. GFR < 15 ml/min (increased bleeding risk)

8. ACS in patients with cancer with platelet count < 50,000

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Important Precautions

🔹 Dyspnea

A common side effect due to increased adenosine levels.

Usually mild and transient; does not require stopping unless severe.

🔹 Bradyarrhythmias

Ticagrelor can cause ventricular pauses, especially early in therapy.

🔹 Drug interactions

Avoid:

Strong CYP3A4 inhibitors (ketoconazole, clarithromycin)

Strong CYP3A4 inducers (rifampicin, phenytoin)

High-dose aspirin

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Advantages Over Clopidogrel

Faster onset

Reversible binding

Consistent platelet inhibition

Better clinical outcomes in ACS

Not affected by genetic polymorphisms (CYP2C19)

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When to Prefer Clopidogrel Instead

High bleeding risk

Severe dyspnea with ticagrelor

Cost concerns

Chronic anticoagulation needed

Very low platelets

Post-CABG needing long-term antiplatelet therapy

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Clinical Pearls

Always pair ticagrelor with low-dose aspirin only.

Avoid in patients with active bleeding or prior hemorrhagic stroke.

Check platelet count, renal function, and hepatic function before starting.

Educate patients on dyspnea—it is common but usually harmless.

Twice-daily dosing requires good compliance.

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