Loading Doses for NSTEMI: Aspirin, Clopidogrel, and Atorvastatin
For patients presenting with NSTEMI, administer aspirin 162-325 mg (non-enteric-coated, chewable) immediately, clopidogrel 600 mg loading dose, and initiate high-intensity statin therapy (atorvastatin 80 mg) as soon as possible without contraindications. 1, 2
Aspirin Loading and Maintenance
- Give 162-325 mg of non-enteric-coated, chewable aspirin immediately upon presentation, even before definitive NSTEMI diagnosis is confirmed 1, 2
- The chewable, non-enteric formulation is critical because enteric-coated aspirin has delayed and reduced absorption, which is unacceptable in acute settings 1
- Continue with 81 mg daily maintenance dose indefinitely after the initial loading 1, 2, 3
- Higher maintenance doses (up to 325 mg) increase bleeding risk without improving outcomes 1
Clopidogrel Loading Strategy
The 600 mg loading dose is strongly preferred over 300 mg because it provides more rapid and reliable platelet inhibition 2, 3, 4
Timing Based on Management Strategy:
For Early Invasive Strategy (planned catheterization):
- Administer clopidogrel 600 mg loading dose before diagnostic angiography ("upstream" therapy) 1, 2
- Follow with 75 mg daily maintenance 1
For Conservative Strategy (no immediate catheterization):
- Give clopidogrel 600 mg loading dose as soon as NSTEMI diagnosis is established 1, 4
- Continue 75 mg daily for up to 12 months 1
Critical Clopidogrel Pitfall:
Withhold clopidogrel loading if CABG is likely within 5-7 days due to significantly increased surgical bleeding risk 1, 2. However, if the diagnosis is definite NSTEMI and an invasive strategy is selected, the thrombotic risk typically outweighs bleeding concerns, and upstream therapy should proceed 1
Atorvastatin (High-Intensity Statin)
Initiate high-intensity statin therapy immediately in all NSTEMI patients without contraindications 1
- Atorvastatin 80 mg daily represents high-intensity statin therapy appropriate for NSTEMI 1
- This is a Class I recommendation with no specific "loading dose" required—simply start the high-intensity daily dose 1
- Obtain fasting lipid profile within 24 hours if feasible, but do not delay statin initiation waiting for lipid results 1
Alternative P2Y12 Inhibitors (When Available)
While clopidogrel is the standard, ticagrelor is preferred over clopidogrel when available for NSTEMI patients 1, 3, 5:
- Ticagrelor loading: 180 mg, then 90 mg twice daily 1, 3
- Prasugrel (60 mg loading, 10 mg daily) may be considered at time of PCI but is contraindicated in patients with prior stroke/TIA 1
Duration of Dual Antiplatelet Therapy
- Continue aspirin plus clopidogrel (or alternative P2Y12 inhibitor) for at least 12 months unless bleeding risk clearly outweighs benefit 1, 3, 5
- After 12 months, continue aspirin indefinitely 1, 5
Common Pitfalls to Avoid
- Never use enteric-coated aspirin initially—absorption is too slow for acute settings 1
- Do not delay aspirin for diagnostic confirmation; give immediately for suspected ACS 2
- Avoid high-dose aspirin maintenance (>81 mg with ticagrelor, >100 mg generally) as it increases bleeding without benefit 1
- Do not give prasugrel upstream (before angiography) in NSTEMI—wait until coronary anatomy is defined at PCI 1
- Check for stroke/TIA history before considering prasugrel (absolute contraindication) 1