How long should aspirin be taken?

Duration of Aspirin Therapy Based on Clinical Indication

The recommended duration of aspirin therapy depends on the specific clinical indication, with long-term indefinite use being appropriate for most patients with established cardiovascular disease, while duration is more limited for certain interventional scenarios.

Primary Prevention (No Existing Cardiovascular Disease)

• For persons aged 50 years or older without symptomatic cardiovascular disease:
  • Low-dose aspirin (75-100 mg daily) may be taken over a long period (at least 10 years) to achieve mortality benefit 1
  • However, benefits are modest and must be weighed against bleeding risk
  • Not recommended for routine use in adults 60 years or older 2
  • For adults 40-59 years with ≥10% 10-year CVD risk, decision should be individualized 2

Secondary Prevention (Established Cardiovascular Disease)

• For patients with established coronary artery disease (CAD):
  • Long-term indefinite use of aspirin (75-162 mg daily) is recommended 1
  • This includes patients with:
    • Prior myocardial infarction
    • Prior revascularization
    • Coronary stenoses >50% by angiogram
    • Evidence of cardiac ischemia on testing

Special Clinical Scenarios

After Acute Coronary Syndrome (ACS)

• First year after ACS without stent placement:
  • Dual antiplatelet therapy (aspirin plus P2Y12 inhibitor) for 12 months 1
  • After 12 months, continue single antiplatelet therapy indefinitely 1

After Percutaneous Coronary Intervention (PCI) with Stent

• For bare-metal stents:

  • Aspirin 162-325 mg daily for at least 1 month 1
  • Then continue aspirin 75-162 mg daily indefinitely 1

• For drug-eluting stents:

  • Aspirin 162-325 mg daily for 3 months (sirolimus-eluting) or 6 months (paclitaxel-eluting) 1
  • Then continue aspirin 75-162 mg daily indefinitely 1
  • Dual antiplatelet therapy recommended for 12 months 1
  • After 12 months, single antiplatelet therapy is recommended over continuation of dual therapy 1

After CABG Surgery

• Post-CABG patients:
  • Aspirin 100-325 mg daily initiated within 6 hours after surgery 3
  • Long-term maintenance dose of 75-162 mg daily indefinitely 3

Optimal Dosing Considerations

• The optimal dose of aspirin for most indications is 75-162 mg daily 1, 4
• Higher doses (>162 mg) do not provide additional cardiovascular protection but increase bleeding risk 4
• The most commonly used low-dose tablet in the US is 81 mg 1

Common Pitfalls and Caveats

1. Premature discontinuation: Stopping aspirin therapy prematurely after stent placement increases risk of stent thrombosis 1

2. Unnecessary high dosing: Using doses higher than 81-162 mg for long-term therapy increases bleeding risk without additional benefit 4

3. Failure to transition: Not switching from higher initial doses (used post-procedure) to lower maintenance doses increases bleeding risk 1

4. Inappropriate primary prevention: Using aspirin for primary prevention in low-risk individuals or those >60 years where harms may outweigh benefits 2

5. Inadequate bleeding risk assessment: Not considering factors such as age, prior GI bleeding, concurrent anticoagulants, or NSAIDs when prescribing long-term aspirin 1

For most patients requiring aspirin for cardiovascular protection, the therapy should be continued indefinitely unless contraindications develop, with appropriate dose adjustments based on the specific clinical scenario and time from the index event.