Is it appropriate to prescribe aspirin (acetylsalicylic acid) to a patient?

Can Aspirin Be Prescribed? A Risk-Stratified Approach

Yes, aspirin can be prescribed, but the decision depends critically on whether the patient has established atherosclerotic cardiovascular disease (ASCVD) versus primary prevention needs, with secondary prevention showing clear benefit while primary prevention requires careful risk-benefit assessment. 1

Secondary Prevention: Strong Indication

For patients with documented ASCVD (prior MI, stroke, coronary revascularization, or significant obstructive CAD), aspirin 75-162 mg daily is strongly recommended as lifelong therapy. 2 The benefits far outweigh bleeding risks in this population. 1

• The most common U.S. dose is 81 mg daily, which minimizes side effects while maintaining efficacy. 1
• For acute coronary syndrome, aspirin should be administered as soon as possible (160-325 mg loading dose). 1
• Following coronary stenting, aspirin combined with a P2Y12 inhibitor (clopidogrel, ticagrelor, or prasugrel) is recommended for up to 6-12 months. 1, 2

Primary Prevention: Selective Use Only

For primary prevention, aspirin is generally NOT recommended in most patients due to bleeding risks that often equal or exceed cardiovascular benefits. 1

When Primary Prevention MAY Be Considered:

Aspirin 75-162 mg daily may be reasonable in highly selected patients who meet ALL of the following criteria: 1, 2

• Age 50-70 years (not older than 70) 1
• Diabetes PLUS at least one additional major risk factor:
  • Family history of premature ASCVD
  • Hypertension
  • Dyslipidemia
  • Current smoking
  • Chronic kidney disease/albuminuria 1
• Low bleeding risk (no anemia, renal disease, or advanced age) 1, 2
• 10-year ASCVD risk >10-15% 2

When Primary Prevention Should NOT Be Used:

• Age <50 years with diabetes but no other major risk factors - bleeding risks outweigh minimal benefits 1
• Age >70 years - greater risk than benefit regardless of risk factors 1
• Low cardiovascular risk (10-year ASCVD risk <6-10%) 2
• Increased bleeding risk: active peptic ulcer disease, bleeding disorders, concurrent anticoagulation, uncontrolled hypertension 2
• Age <21 years - contraindicated due to Reye syndrome risk 1

Critical Bleeding Risk Considerations

The ASCEND trial demonstrated that while aspirin reduced vascular events by 12%, major bleeding increased by 29% (from 3.2% to 4.1%), primarily gastrointestinal bleeding. 1 For patients with ASCVD risk >1% per year, the number of events prevented roughly equals the number of bleeding episodes induced, though these complications have different long-term health impacts. 1

Practical Dosing Algorithm

• Secondary prevention: 75-100 mg daily (81 mg in U.S.) 1, 2
• Acute coronary syndrome: 160-325 mg loading dose, then 75-162 mg daily 1
• Primary prevention (if indicated): 75-162 mg daily (typically 81 mg) 1, 2

Common Pitfalls to Avoid

• Do not prescribe aspirin for primary prevention in patients >70 years - the balance clearly favors harm. 1
• Do not use aspirin in patients with uncontrolled hypertension - dramatically increases bleeding risk. 2
• Do not assume all diabetic patients need aspirin - only those with additional risk factors and age 50-70 years should be considered. 1
• Do not forget shared decision-making - patients must understand that bleeding risks are comparable to cardiovascular benefits in primary prevention. 1

Alternative for Aspirin Intolerance

For patients with documented aspirin allergy who require antiplatelet therapy, clopidogrel 75 mg daily is the recommended alternative. 2