What is the role of aspirin (antiplatelet agent) in the treatment of pericarditis?

Aspirin in Pericarditis: Anti-inflammatory Agent, Not Antiplatelet

Aspirin is recommended as a first-line anti-inflammatory therapy for pericarditis at high doses (500-1,000 mg every 6-8 hours), not for its antiplatelet effects, and should be combined with colchicine to reduce recurrence risk. 1

Mechanism and Dosing

• High-dose aspirin (750-1,000 mg every 8 hours or 500-1,000 mg every 6-8 hours) functions as an anti-inflammatory agent through COX inhibition, not as an antiplatelet drug. 1, 2
• The anti-inflammatory dose is substantially higher than the antiplatelet dose (81-325 mg daily used for cardiovascular protection). 1
• Treatment should continue until complete symptom resolution and CRP normalization, typically 1-2 weeks, followed by gradual tapering. 2, 3

First-Line Therapy Algorithm

Aspirin PLUS colchicine is the recommended initial regimen: 1, 2

• Aspirin: 750-1,000 mg every 8 hours with gastroprotection 2, 4
• Colchicine: 0.5 mg twice daily (≥70 kg) or 0.5 mg once daily (<70 kg) for 3 months 1
• Duration: Continue until symptoms resolve and CRP normalizes, then taper aspirin gradually 2, 3

Special Clinical Contexts

Post-MI Pericarditis

• Aspirin is the preferred NSAID in post-MI pericarditis because other NSAIDs may impair myocardial healing and increase rupture risk. 1
• Acetaminophen can be used for symptomatic relief in early post-MI pericarditis (1-3 days post-infarction). 1
• For persistent symptoms or late pericarditis (Dressler's syndrome), high-dose aspirin (650 mg every 4-6 hours) should be initiated. 1
• Glucocorticoids and non-aspirin NSAIDs are potentially harmful post-MI due to increased risk of recurrent MI, impaired healing, and ventricular rupture. 1

Aspirin vs. Other NSAIDs

• Aspirin is preferred in patients with coronary artery disease, heart failure, or renal disease. 3
• Ibuprofen (600 mg every 8 hours) is an alternative in patients without CAD, HF, or renal disease. 2, 3
• Aspirin should be avoided in aspirin-naïve patients with asthma and nasal polyps due to risk of bronchospasm. 3

Pediatric Considerations

• Aspirin is NOT recommended in children due to risk of Reye's syndrome and hepatotoxicity. 1
• High-dose NSAIDs (not aspirin) are first-line in pediatric pericarditis. 1

Monitoring and Tapering

• CRP should guide treatment duration and assess therapeutic response. 1, 2
• Tapering should only begin when symptoms are absent and CRP is normalized. 2, 3
• Inadequate treatment duration before tapering is a common cause of recurrence. 2, 5
• Exercise restriction should continue until symptom resolution and normalization of CRP, ECG, and echocardiogram. 2, 4

When Aspirin Fails or Is Contraindicated

Second-line therapy hierarchy: 2

1. Low-dose corticosteroids (prednisone 0.2-0.5 mg/kg/day) only when NSAIDs/colchicine fail or are contraindicated 2, 4
2. Corticosteroids increase risk of chronicity and recurrence, so they should NOT be first-line. 1, 2
3. For corticosteroid-dependent recurrent pericarditis: IVIG, anakinra (IL-1 antagonist), or azathioprine 2

Critical Pitfalls to Avoid

• Do not use low-dose "antiplatelet" aspirin (81-325 mg) for pericarditis—this dose is ineffective for inflammation. 1, 3
• Do not start corticosteroids as first-line therapy; they provide rapid symptom control but significantly increase recurrence risk. 1, 2, 4
• Do not use non-aspirin NSAIDs in post-MI pericarditis due to risk of impaired healing and rupture. 1
• Do not taper aspirin before symptoms resolve and CRP normalizes. 2, 3
• Always add colchicine to aspirin—colchicine reduces recurrence from 30% to 15%. 1, 5