What is the recommended dose of aspirin (acetylsalicylic acid) for cardiovascular protection in patients over 75 years old?

Aspirin Dosing in Patients Over 75 Years

For patients over 75 years old requiring aspirin for cardiovascular protection, use 75 mg daily without a loading dose in most clinical scenarios, with the critical exception being acute coronary syndromes where standard loading doses apply regardless of age.

Acute Coronary Syndromes (STEMI/NSTEMI)

Loading Dose

• Administer 162-325 mg loading dose immediately upon presentation, regardless of age 1, 2
• This applies even to patients already on maintenance aspirin therapy 2
• Use non-enteric coated formulation and have patient chew the tablet for faster onset 2

Maintenance Dose After Acute Event

• For patients >75 years: 75-100 mg daily (81 mg is the standard U.S. formulation) 1, 2
• Continue indefinitely as secondary prevention 1

Dual Antiplatelet Therapy Considerations in Elderly

With Clopidogrel

• Critical age-specific modification: For patients >75 years receiving clopidogrel after STEMI, give NO loading dose of clopidogrel (skip the 300 mg load), start directly with 75 mg daily 1
• Combine with aspirin 75-100 mg daily 1
• This reduced clopidogrel approach in elderly patients >75 years reflects increased bleeding risk 1

With Prasugrel

• Prasugrel is generally NOT recommended in patients ≥75 years due to increased risk of fatal and intracranial bleeding 1
• May consider only in very high-risk situations (diabetes or prior MI) where benefit may outweigh risk 1

Secondary Prevention (Stable Coronary Disease)

• Use 75-100 mg daily (81 mg standard U.S. dose) for long-term maintenance 1, 2
• This lower dose range (75-81 mg) optimizes efficacy while minimizing bleeding risk, which is particularly important in elderly patients 1, 3

Primary Prevention in Patients >75 Years

Do not initiate aspirin for primary prevention in patients ≥75 years old 1, 4

Key Evidence

• The balance of benefits versus bleeding risks is unfavorable in this age group 1
• For patients over 70 years without established cardiovascular disease, aspirin carries greater risk than benefit 1
• The 2022 U.S. Preventive Services Task Force recommends against initiating aspirin in adults ≥60 years for primary prevention 4

Bleeding Risk Mitigation

Critical Considerations in Elderly

• Older age is an independent risk factor for bleeding complications 1
• Major gastrointestinal bleeding risk increases to 4-12 per 1,000 older persons over 5 years (compared to 2-4 per 1,000 in middle-aged adults) 2
• Always use the lowest effective dose (75-81 mg) in elderly patients to minimize bleeding while maintaining efficacy 1, 3

Contraindications

• Active bleeding or bleeding tendency 2
• Concurrent anticoagulation (requires careful risk-benefit assessment) 1, 2
• Recent gastrointestinal bleeding 2
• Uncontrolled hypertension 2

Common Pitfalls to Avoid

• Do not use higher maintenance doses (>100 mg) in elderly patients - doses above 100 mg show no additional efficacy benefit but may increase bleeding risk, especially when combined with clopidogrel 3
• Do not give clopidogrel loading dose (300 mg) to patients >75 years in acute settings - start directly with 75 mg maintenance dose 1
• Do not continue or initiate aspirin for primary prevention in patients >75 years - bleeding risks outweigh cardiovascular benefits in this population 1, 4
• Do not use prasugrel routinely in patients ≥75 years - associated with increased fatal bleeding 1

Dosing Algorithm Summary

For patients >75 years:

1. Acute MI/ACS: 162-325 mg loading dose → 75-100 mg daily maintenance 1, 2
2. Established CVD (secondary prevention): 75-100 mg daily 1, 2
3. Primary prevention: Do not initiate 1, 4
4. With clopidogrel: Aspirin 75-100 mg + clopidogrel 75 mg (no clopidogrel loading dose) 1
5. Preferred maintenance dose: 75-81 mg daily to optimize safety profile 1, 3