Overview
NSAID that irreversibly inhibits COX-1 → blocks TXA2 formation → platelet inhibition. Used for CAD, stroke prevention, post-stent therapy. Foundation of antiplatelet therapy.
Dosing
CAD secondary prevention: 81mg daily ACS: 162-325mg loading, then 81mg daily TIA/stroke: 50-325mg daily Post stent: 81mg daily (with DAPT) Max dose: 325mg daily for CV indications
Pharmacokinetics
Onset: 30min Peak: 1-2hr Duration: 7-10 days (platelet lifespan) Metabolism: Hepatic Elimination: Renal Half-life: 2-3hr (15min for antiplatelet effect)
Pharmacodynamics
Mechanism: Irreversible COX-1 inhibition → blocks TXA2 production Effects: - Antiplatelet (lasts platelet lifespan) - Anti-inflammatory at higher doses - GI irritation - Increased bleeding time
Clinical Considerations
Clinical Pearls: 1. Chew for rapid ACS effect 2. Don't stop abruptly in CAD 3. GI protection with PPI if high risk 4. Avoid in children with viral illness (Reye's) 5. Dual therapy with clopidogrel/ticagrelor post-stent 6. Low-dose (81mg) as effective as higher doses 7. Withhold 7d before elective surgery 8. Consider in preeclampsia prophylaxis