What is the recommended use and dosage of prasugrel (a P2Y12 inhibitor) for a patient with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI)?

Prasugrel for Acute Coronary Syndrome with PCI

Prasugrel (60 mg loading dose, then 10 mg daily) plus aspirin is recommended for P2Y12 inhibitor-naïve patients with acute coronary syndrome undergoing percutaneous coronary intervention, unless contraindications exist. 1

Indications and Patient Selection

Prasugrel is indicated specifically for ACS patients managed with PCI, including:

• Unstable angina or non-ST-elevation myocardial infarction (NSTEMI) 1, 2
• ST-elevation myocardial infarction (STEMI) when managed with primary or delayed PCI 1, 2

Prasugrel should be considered in preference to ticagrelor for NSTE-ACS patients who proceed to PCI (Class IIa recommendation). 1

Dosing Regimen

Loading Dose

• 60 mg oral loading dose 1, 3, 2
• Administer after coronary anatomy is known in UA/NSTEMI patients to avoid dosing those requiring urgent CABG 1, 2
• In STEMI patients presenting within 12 hours of symptom onset, may give at time of diagnosis, though most receive it at time of PCI 2

Maintenance Dose

• Standard: 10 mg once daily 1, 3, 2
• Low body weight (<60 kg): Consider 5 mg once daily due to increased bleeding risk, though this dose has not been prospectively studied 1, 4, 2
• Age ≥75 years: Consider 5 mg once daily due to increased fatal and intracranial bleeding risk 1, 2

Duration

• Continue for 12 months in combination with aspirin (75-100 mg daily) 1, 3, 5

Absolute Contraindications

Do not use prasugrel in patients with:

• Prior transient ischemic attack (TIA) or stroke - this is a Class III (Harm) recommendation due to significantly increased risk of intracranial hemorrhage (6.5% stroke rate with prasugrel vs 1.2% with clopidogrel in this population) 1, 6, 3, 2
• Active pathological bleeding (peptic ulcer, intracranial hemorrhage) 2
• Hypersensitivity to prasugrel 2

Relative Contraindications and High-Risk Populations

Exercise caution or avoid prasugrel in:

• Age ≥75 years: Generally not recommended except in high-risk situations (diabetes or prior MI) where benefit may outweigh risk; if used, consider 5 mg maintenance dose 7, 2
• Body weight <60 kg: Increased exposure to active metabolite and bleeding risk; consider 5 mg maintenance dose 1, 4, 2
• Patients likely to undergo urgent CABG: Do not start prasugrel 2

Timing Considerations

When to administer the loading dose:

• In UA/NSTEMI: After coronary anatomy is established to avoid dosing patients requiring CABG 1, 2
• In STEMI presenting >12 hours after symptom onset: After coronary anatomy is known 1
• In STEMI presenting ≤12 hours: May give at diagnosis, though typically given at time of PCI 2

A 2009 trial of 4,033 NSTEMI patients showed no clear benefit when prasugrel was given before diagnostic angiography compared to at time of PCI, but bleeding risk increased with early administration. 2

Perioperative Management

Discontinue prasugrel at least 7 days before planned CABG to allow dissipation of antiplatelet effect, unless the need for revascularization outweighs bleeding risk. 1, 4

Efficacy vs Clopidogrel

Prasugrel demonstrates superior platelet inhibition compared to clopidogrel:

• 82.5% vs 71.1% inhibition at 4 hours after loading dose 8
• 84.1% vs 67.4% inhibition at 30 days during maintenance 8
• Reduced composite endpoint of cardiovascular death, nonfatal MI, or nonfatal stroke compared to clopidogrel 2, 9
• Particularly effective in patients with diabetes mellitus 9

Bleeding Risk

Prasugrel increases bleeding risk compared to clopidogrel, particularly:

• TIMI Major bleeding more common with prasugrel 2
• Excess bleeding occurs predominantly during maintenance phase (after day 3), not during loading phase 10
• Fatal intracranial bleeding risk highest in patients ≥75 years, <60 kg body weight, or prior stroke/TIA 7, 2, 9

Bleeding risk mitigation strategies:

• Use radial artery access over femoral for PCI 3, 11
• Maintain aspirin at 75-100 mg daily (not higher doses) 1, 3, 11
• Prescribe a proton pump inhibitor with dual antiplatelet therapy to reduce gastrointestinal bleeding (Class I recommendation) 3, 5, 11

Common Pitfalls to Avoid

• Never administer prasugrel to patients with prior stroke or TIA - this is contraindicated and increases intracranial hemorrhage risk 1, 6, 3, 2
• Do not give prasugrel before knowing coronary anatomy in UA/NSTEMI patients who may require urgent CABG 1, 2
• Do not use standard 10 mg maintenance dose in patients ≥75 years or <60 kg without considering dose reduction to 5 mg 1, 4, 2
• Do not discontinue prasugrel prematurely, particularly in first few weeks after ACS, as this increases risk of subsequent cardiovascular events 2
• Do not fail to prescribe a PPI with dual antiplatelet therapy 3, 5, 11