Aspirin
ASA
Pronunciation: AS-pir-in
““Aspirin’ Echo trainer” / “Asa, the Aspirin’ Bear””
Bear for Bayer
Asa for A.S.A. = Acetylsalicylic acid
Echo Trainer for Ecotrin
What it isIrreversible COX-1 and COX-2 inhibitor; secondary cardiovascular prevention, acute coronary syndrome and stroke.
Why this oneIts irreversible platelet effect persists for each platelet's lifespan, distinguishing it from other NSAIDs.
What limits itGI bleeding limits use; primary prevention rarely justifies it. Avoid in viral illness in children; ibuprofen taken first blunts platelet effect.
Pearls
- Enteric coating eases dyspepsia but does not prevent ulcers.
- One dose can trigger bronchospasm in aspirin-sensitive asthma.
- After VTE: no substitute for anticoagulation; reasonable once anticoagulation stops.
- Accepted VTE prophylaxis after hip or knee replacement.
Aspirin prescription history
Animated chart of estimated U.S. prescriptions per year, Antithrombotics (1914–2026). Aspirin enters in 1899 (estimated).
FDA-approved for
- pain/fever (~1899)
- antiplatelet (~1985)
Principal riskGI bleeding, and Reye syndrome in children
Classes and tags
Clinical profile
FDA label
Read the full label on DailyMed ↗
NO BOXED WARNINGS
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Temporary relief of minor aches and pains (delayed release — not for fast relief) | Adults & children ≥12 yr | 4 × 81 mg tablets q4h PRN | 4–8 × 81 mg tablets q4h while symptoms last | 48 × 81 mg tablets/24 h unless directed by a doctor |
Renal Undefined
Hepatic Undefined
81 mg delayed-release (safety coated) tablet; tablet counts apply only to this 81 mg product, not higher-strength aspirin tablets.
Instructions
- Drink a full glass of water with each dose.
- Children <12 yr: ask a doctor (no OTC dose given).
- Do not exceed 48 × 81 mg tablets in 24 h unless directed by a doctor.
Available strengths
- tab 81, 325, 500 mg
- cap 81, 325 mg
- DR tab 81, 325 mg
- chew tab 81 mg
- supp 300 mg
Pregnancy Undefined
Lactation Undefined
Cost
| Strength | #/mo | generic $/unit | CostPlus | |
|---|---|---|---|---|
| 81 mg | tab | per unit | $0.01/ea | offered |
| 325 mg | tab | per unit | $0.02/ea | not offered |
| 500 mg | tab | per unit | not offered |
Open Aspirin in the interactive console ↗
Memory aids: interaction avatars
Open Aspirin in the interactive console ↗
Self-check
- How long does aspirin’s platelet effect persist?
Each platelet’s lifespan. - Which drug taken first blunts aspirin’s platelet effect?
Ibuprofen.