Can aspirin (acetylsalicylic acid) be prescribed?

Can Aspirin Be Prescribed?

Yes, aspirin can and should be prescribed, but the indication determines whether it is appropriate—it is strongly recommended for secondary prevention in patients with established cardiovascular disease, while primary prevention requires careful risk stratification and is generally not recommended for low-risk individuals. 1

Secondary Prevention: Strong Indication

Aspirin is definitively indicated and should be prescribed in the following situations:

• Established atherosclerotic cardiovascular disease (ASCVD): Aspirin 75-100 mg daily is recommended as lifelong therapy for patients with previous myocardial infarction, stroke, or revascularization 1
• Documented coronary artery disease: Patients with significant obstructive CAD on imaging should receive aspirin 75-100 mg daily 1
• Post-acute coronary syndrome: Following coronary stenting, aspirin 75-100 mg daily combined with clopidogrel for up to 6 months is the default strategy 1
• Diabetes with established ASCVD: Aspirin 75-162 mg/day is recommended as secondary prevention 2, 1

For these secondary prevention indications, the benefits far outweigh bleeding risks, and aspirin therapy is mandatory unless contraindicated 2

Primary Prevention: Selective Use Based on Risk

Primary prevention with aspirin requires careful patient selection and is NOT universally recommended. The evidence has shifted substantially against routine primary prevention in recent years 3

When Primary Prevention May Be Considered:

• High-risk diabetic patients: Men and women aged ≥50 years with diabetes PLUS at least one additional major risk factor (hypertension, dyslipidemia, smoking, family history of premature ASCVD, or chronic kidney disease/albuminuria) who are NOT at increased bleeding risk 2, 1
• Elevated coronary artery calcium (CAC): Patients with CAC ≥100 may benefit from aspirin 81 mg daily if they lack bleeding contraindications 2
• High cardiovascular risk women: Aspirin 81 mg daily or 100 mg every other day for stroke prevention when 10-year risk is sufficiently high (>6-10%) 1

When Primary Prevention Should NOT Be Used:

• Low-risk individuals: Men and women aged <50 years with diabetes but no other major ASCVD risk factors—bleeding risks outweigh minimal benefits 2, 1
• Elderly patients without established CVD: For patients over age 70 years without documented cardiovascular disease, risks exceed benefits 2, 4
• CAC score of zero: Bleeding risk outweighs benefit when CAC = 0, unless 10-year ASCVD risk exceeds 20% 2
• General population without risk factors: Aspirin is not recommended for routine primary prevention in low-risk persons 1

Absolute Contraindications (FDA Label)

Do not prescribe aspirin in these situations: 5

• Aspirin allergy or previous allergic reaction
• Active peptic ulcer disease
• Bleeding disorders or recent gastrointestinal/intracranial bleeding
• Severe liver disease or renal failure
• Thrombocytopenia (low platelet count)
• Children and teenagers with viral illnesses (risk of Reye syndrome—contraindicated in patients <21 years) 2, 5
• Concurrent anticoagulant therapy increases bleeding risk 3-6 fold 2
• Uncontrolled hypertension 1
• Last 3 months of pregnancy unless specifically directed by physician 5

Dosing Recommendations

The optimal dose varies by indication:

• Secondary prevention: 75-100 mg daily 1
• Primary prevention: 75-81 mg daily (most common US formulation is 81 mg) 2, 1
• Acute coronary syndrome: Initial dose 160-325 mg, then 75-100 mg daily 1, 6
• Acute ischemic stroke: 160-325 mg 6
• Atrial fibrillation (when anticoagulation not used): 325 mg daily 6

Higher doses do not provide additional cardiovascular benefit and increase bleeding risk 2

Critical Bleeding Risk Assessment

The major harm from aspirin is bleeding, which must be weighed against cardiovascular benefits:

• Gastrointestinal bleeding increases with odds ratio 1.59, adding 0.29 events per 1,000 person-years 2
• Intracranial bleeding increases with odds ratio 1.27, adding 0.1 events per 1,000 person-years 2
• Bleeding risk increases with age (incidence rate ratio 1.05 per year of age) 2
• Major bleeding occurs approximately twice as frequently with aspirin therapy 1
• In the ASCEND trial of diabetic patients, major bleeding increased from 3.2% to 4.1% over 7.4 years 2

For adults with ASCVD risk >1% per year, the number of cardiovascular events prevented approximates the number of bleeding episodes induced, though these complications have different long-term health impacts 2

Common Clinical Pitfalls to Avoid

• Do not prescribe aspirin for primary prevention in patients over 70 years without established CVD—the 2018 ASPREE trial and subsequent guidelines have clearly shown net harm in this population 2, 3
• Do not use aspirin in diabetic patients with asymptomatic peripheral artery disease as primary prevention—evidence does not support benefit 1
• Do not combine aspirin with NSAIDs or anticoagulants without gastroprotection—consider proton pump inhibitor co-administration 2
• Do not prescribe doses higher than 100 mg for chronic prevention—no additional benefit and increased bleeding 2, 7
• Do not stop aspirin 7-10 days before surgery in patients with established CVD—discuss with surgical team as cardiovascular risk may outweigh bleeding risk 2

Alternative When Aspirin Cannot Be Used

Clopidogrel 75 mg daily is the recommended alternative for patients with documented aspirin intolerance or allergy 1