What is the recommended daily dose of aspirin (acetylsalicylic acid) for antiplatelet therapy?

Recommended Aspirin Dosage for Antiplatelet Therapy

For antiplatelet therapy, a daily aspirin dose of 75-100 mg is recommended for long-term maintenance therapy based on the most recent guidelines. 1

Initial Loading Dose vs. Maintenance Dose

Initial Loading Dose

• For acute coronary syndromes (ACS) or situations requiring immediate antithrombotic effect:
  • Loading dose of 162-325 mg should be administered 1
  • Aspirin should be chewed (non-enteric coated) when possible for faster onset of action 1
  • This higher initial dose ensures rapid and complete inhibition of thromboxane A2-dependent platelet aggregation 1

Maintenance Dose

• After initial loading, transition to a daily maintenance dose of 75-100 mg 1
• This lower maintenance dose:
  • Is equally effective as higher doses for preventing cardiovascular events 2
  • Has significantly lower risk of gastrointestinal bleeding complications 2
  • Exceeds the minimal effective dose required for platelet thromboxane A2 suppression 1

Specific Clinical Scenarios

Acute Coronary Syndrome

• Initial loading: 162-325 mg
• Maintenance: 75-100 mg daily 1
• When used with ticagrelor, aspirin dose should always be ≤100 mg daily 1

Post-PCI with Stent Placement

• For first 3-6 months after drug-eluting stent (DES): 75-100 mg daily with clopidogrel 75 mg daily 1
• After 12 months: Single antiplatelet therapy with aspirin 75-100 mg daily 1

Medical Management of ACS (without revascularization)

• Maintenance: 75-100 mg daily with P2Y12 inhibitor for at least 12 months 1

Post-CABG for ACS

• P2Y12 inhibitor therapy should be resumed after CABG with aspirin 75-100 mg daily to complete 12 months of dual antiplatelet therapy 1

Evidence Supporting Lower Maintenance Doses

The CURRENT-OASIS trial directly compared higher-dose (≥300 mg/day) versus low-dose aspirin (75-81 mg/day) in over 25,000 ACS patients and found similar efficacy outcomes between the two dosing strategies, but with increased bleeding risk at higher doses 2, 3.

Multiple guidelines consistently recommend the 75-100 mg daily maintenance dose based on:

1. Equal efficacy compared to higher doses 2
2. Significantly lower risk of gastrointestinal bleeding 2
3. Sufficient platelet inhibition at this dose range 1

Common Pitfalls to Avoid

• Using unnecessarily high maintenance doses: Higher maintenance doses (>100 mg) do not provide additional cardiovascular protection but increase bleeding risk 2
• Failing to provide an adequate loading dose: In acute settings, a loading dose of 162-325 mg is necessary for rapid platelet inhibition 1
• Using enteric-coated aspirin in acute settings: Non-enteric coated aspirin should be used and chewed when possible for faster onset of action in acute settings 1
• Inappropriate dosing with ticagrelor: When using ticagrelor, aspirin dose should always be ≤100 mg daily 1

In conclusion, while an initial loading dose of 162-325 mg is appropriate in acute settings, the optimal maintenance dose of aspirin for antiplatelet therapy is 75-100 mg daily, which provides effective cardiovascular protection while minimizing bleeding risk.