Prasugrel for Acute Coronary Syndrome
Prasugrel is a potent P2Y12 inhibitor indicated specifically for patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI), administered as a 60 mg loading dose followed by 10 mg daily maintenance (or 5 mg daily if body weight <60 kg), and should be continued for 12 months unless bleeding risk is excessive. 1, 2
Indications
Prasugrel is FDA-approved and guideline-recommended for:
- Unstable angina or non-ST-elevation myocardial infarction (NSTEMI) undergoing PCI 1, 2
- ST-elevation myocardial infarction (STEMI) managed with either primary or delayed PCI 1, 2
The 2025 ACC/AHA guidelines give prasugrel a Class 1, Level B-R recommendation for both NSTE-ACS and STEMI patients undergoing PCI, stating it "should be administered to reduce MACE and stent thrombosis" 1. Prasugrel is preferred over clopidogrel due to more potent and rapid platelet inhibition, though it carries higher bleeding risk 1.
Critical distinction: Prasugrel is NOT recommended for medically managed ACS patients who do not undergo PCI—this is an absolute contraindication per ESC guidelines 3.
Absolute Contraindications
Do not use prasugrel in patients with: 2
- Prior stroke or transient ischemic attack (TIA) - This is a boxed warning due to worse net clinical outcomes and increased fatal bleeding 1, 2
- Active pathological bleeding 2
- Hypersensitivity to prasugrel or any thienopyridine 2
- Patients likely to undergo urgent CABG - discontinue at least 7 days before surgery when possible 2
Relative Contraindications and Cautions
Age ≥75 years: Prasugrel is generally not recommended in elderly patients except in high-risk subgroups (diabetes mellitus or prior MI), where use "may be considered" 2. The bleeding risk substantially outweighs benefit in most patients over 75 1, 2.
Body weight <60 kg: Consider dose reduction to 5 mg daily maintenance dose (after standard 60 mg loading dose) 1, 2. These patients have 10.1% major/minor bleeding rates versus 4.2% in heavier patients 2.
Propensity to bleed or concomitant medications increasing bleeding risk: Exercise caution and consider alternative agents 2.
Real-world data shows approximately 30-38% of ACS patients have at least one contraindication or condition requiring special attention for prasugrel use 4, 5.
Dosing Regimen
Loading dose: 60 mg orally as a single dose 1, 2
- 10 mg once daily for patients ≥60 kg and age <75 years
- 5 mg once daily for patients <60 kg or age ≥75 years (if used at all in elderly)
Concomitant aspirin: 75-100 mg daily (never exceed 100 mg with any P2Y12 inhibitor) 1
Administration: Can be taken with or without food 2
Duration of Therapy
Standard duration: 12 months of dual antiplatelet therapy (DAPT) with aspirin plus prasugrel 1, 3. This is a Class 1 recommendation from both ACC/AHA and ESC guidelines.
Exceptions for shorter duration (<12 months):
- Patients with excessive bleeding risk (e.g., PRECISE-DAPT score ≥25) 3
- Occurrence of actionable bleeding should prompt immediate reassessment of DAPT regimen 3
Critical warning: Premature discontinuation of prasugrel increases risk of stent thrombosis, myocardial infarction, and death 2. Any lapses in therapy should be avoided, and if temporarily discontinued due to adverse events, restart as soon as possible 2.
Bleeding Risk Profile
Prasugrel carries significantly higher bleeding risk than clopidogrel but similar rates to ticagrelor:
- Non-CABG TIMI major bleeding: 2.2% (vs 1.7% with clopidogrel) 2, 6
- Life-threatening bleeding: 1.3% (vs 0.8% with clopidogrel) 2, 6
- Fatal bleeding: 0.3-0.4% (vs 0.1% with clopidogrel) 2, 6
CABG-related bleeding is particularly concerning: 14.1% major/minor bleeding if prasugrel given within 7 days of surgery (vs 4.5% with clopidogrel) 2. This risk decreases substantially if last dose was 4-7 days prior to surgery 2.
Bleeding peaks early: Highest rates occur in the first 7 days after initiation 2. Suspect bleeding in any hypotensive patient who recently underwent invasive procedures 2.
Comparative Efficacy
The landmark TRITON-TIMI 38 trial demonstrated prasugrel superiority over clopidogrel: 9.9% vs 12.1% for the composite of cardiovascular death, MI, or stroke (HR 0.81, p<0.001) 6. This translates to preventing 23 MIs per 1000 patients treated, at the cost of 6 additional major bleeding events 7.
Recent head-to-head comparisons with ticagrelor show equipoise: Meta-analyses found no significant differences in mortality, MACE, or bleeding between prasugrel and ticagrelor 8. However, a 2021 subgroup analysis suggested prasugrel may be superior to ticagrelor specifically in STEMI patients undergoing PCI (9.8% vs 7.1% for primary endpoint, p=0.005) 9, though this requires confirmation in dedicated trials.
Clinical Pearls and Pitfalls
Proton pump inhibitor (PPI): Always co-prescribe a PPI with DAPT to reduce GI bleeding risk 3. Pantoprazole or rabeprazole preferred over omeprazole/esomeprazole due to lower drug-drug interaction potential 3.
Switching from clopidogrel: Can load with prasugrel 60 mg regardless of prior clopidogrel timing or dose 1.
Opioid co-administration: May decrease prasugrel exposure; consider parenteral antiplatelet agents in this setting 2.
Thrombotic thrombocytopenic purpura (TTP): Rare but serious complication that can occur after brief exposure (<2 weeks); requires urgent plasmapheresis 2.
Do not use platelet function testing to guide prasugrel dosing—this is not recommended 3.