Antiplatelet Medications: Preventing Arterial Clots
Antiplatelets prevent blood cells (platelets) from clumping together to form clots. Unlike anticoagulants which target clotting proteins, antiplatelets make platelets less 'sticky.' They're essential after heart attacks and stents.
Key Benefits
Taking This Medicine
Dosage Form
Aspirin: 81mg, 325mg tablets; Clopidogrel: 75mg, 300mg tablets; Ticagrelor: 60mg, 90mg tablets; Prasugrel: 5mg, 10mg tablets
When to Take
Once daily (ticagrelor twice daily), with or without food (aspirin take with food to reduce stomach upset)
Food Instructions
Can be taken with or without food
Common Side Effects
- Bleeding
- Bruising easily
- Upset stomach (especially aspirin)
- Rash (uncommon)
When to Call Your Doctor
- •Bleeding risk
- •Do not stop before surgery without medical advice
- •Stent thrombosis risk if stopped prematurely
- •TTP risk (rare but serious with clopidogrel)
- •Aspirin can cause ulcers
What These Medicines Do
Antiplatelet medications work by preventing platelets (the blood cells responsible for clumping) from sticking together. Unlike anticoagulants which target clotting proteins, antiplatelets target the cells themselves.
Think of platelets like bricklayers in clot construction. Antiplatelets remove some of their tools—they can still do basic work, but they can't build the large, dangerous clots that cause heart attacks and strokes.
Antiplatelets vs Anticoagulants
Antiplatelets: Target platelets, prevent ARTERIAL clots (heart attack, stroke, PAD). Examples: aspirin, clopidogrel, ticagrelor.AHA/ASA Stroke Guidelines, 2021
Anticoagulants: Target clotting proteins, prevent VENOUS clots (DVT, PE) and clots in AFib. Examples: warfarin, DOACs, heparin.
Some patients need both (especially after acute coronary syndrome or stent).ACC/AHA ACS Guidelines, 2024
Types of Antiplatelets
Aspirin:
- Oldest, most studied antiplatelet
- Irreversibly inhibits COX-1 enzyme
- Low dose (81mg) sufficient for most indications
- First-line for cardiovascular preventionUSPSTF Guidelines, 2022
P2Y12 Inhibitors (clopidogrel, prasugrel, ticagrelor):
- More potent than aspirin alone
- Critical after stents and acute coronary syndrome
- Clopidogrel: Standard, widely used, needs activation by liverCAPRIE Trial, NEJM 1996
- Prasugrel: More potent, contraindicated in stroke/TIA, higher bleedingTRITON-TIMI 38 Trial, NEJM 2007
- Ticagrelor: Twice daily, more potent, reversible, dyspnea side effectPLATO Trial, NEJM 2009
Common Things You Might Notice
Bleeding-Related Side Effects:
Side Effects
| Side Effect | Frequency | Management |
|---|---|---|
| Easy bruising | Very common | Usually not serious, avoid trauma |
| Nosebleeds | Common | Pressure for 10-15 minutes, humidifier |
| Bleeding gums | Common | Soft toothbrush, gentle flossing |
| Stomach upset (aspirin) | Common | Take with food, enteric-coated formulations |
| Rash | Uncommon | May indicate allergy, contact doctor |
| Dyspnea (ticagrelor) | Common | Usually mild, tolerable, resolves with discontinuation |
Clopidogrel Resistance (CYP2C19)
About 30% of people have genetic variation (CYP2C19 loss-of-function) that makes clopidogrel less effective.Circulation Genomics, 2019 These "poor metabolizers" may not get full protection from clopidogrel. Alternatives include ticagrelor or prasugrel (which don't require activation). Genetic testing can identify poor metabolizers.
When to Call Your Doctor
Seek Immediate Care For:
- Any serious bleeding: Can't control with pressure, vomiting blood, black tarry stools
- Head injury: Especially if on anticoagulants too
- Sudden severe headache: Could indicate intracranial bleeding
Contact Your Doctor For:
- Planning surgery or procedures: Antiplatelets must be stopped ahead of time
- Significant unexplained bruising or bleeding
- Black, tarry stools or vomiting blood
- New-onset severe headache
- Rash or allergic symptoms
Daily Practical Tips
- Take consistently: Same time daily, especially important for ticagrelor (twice daily)
- Don't stop without approval: Especially critical after stent placement
- Wear medical alert: List antiplatelet medications
- Tell all providers: Especially before procedures or surgery
- Use soft toothbrush: Reduces gum bleeding
- Take aspirin with food: Reduces stomach upset
- Limit alcohol: Can increase bleeding risk and stomach irritation
- Avoid NSAIDs: Increase bleeding risk and stomach damage
Pregnancy & Breastfeeding
- Aspirin: Generally avoided in pregnancy (especially third trimester), low-dose may be used in certain situations
- Clopidogrel/Prasugrel/Ticagrelor: Generally avoided, use only if clearly needed
- Breastfeeding: Aspirin compatible; other antiplatelets use with caution
Food & Medicine Interactions
Drug Interactions
| Interaction | Effect | What to Do |
|---|---|---|
| NSAIDs (ibuprofen, naproxen) | Increase bleeding risk, stomach damage | Avoid while on antiplatelets, especially aspirin |
| Warfarin/DOACs | Increased bleeding risk | May be used together for high-risk patients (DAPT + anticoagulant) |
| SSRI antidepressants | Increased bleeding risk | Monitor for bleeding, may be used together |
| Omeprazole/PPIs | May reduce clopidogrel effectiveness | Use pantoprazole instead if needed |
| Alcohol | Increased bleeding and stomach irritation | Limit to 1-2 drinks daily maximum |
For Healthcare Professionals
Clinical InformationIndications
Primary Prevention:
- Aspirin 81mg daily for select patients (age 40-70 with higher CV risk but low bleeding risk)
- Not recommended routinely for all adults
Secondary Prevention:
- Aspirin 81-162mg daily indefinitely after CAD, stroke, PAD
- DAPT (aspirin + P2Y12) after ACS or stent
Dosing
- Aspirin: 81mg to 325mg daily (81mg standard for maintenance)
- Clopidogrel: 75mg daily (300-600mg loading dose for ACS)
- Prasugrel: 10mg daily (60mg loading), contraindicated with prior stroke/TIA, age ≥75, weight ＜ 60kg
- Ticagrelor: 90mg twice daily (180mg loading), can be used regardless of CYP2C19 status
Bleeding Management
- Minor bleeding: Local measures, continue antiplatelet
- Moderate bleeding: Hold temporarily, resume when bleeding controlled
- Major bleeding: Discontinue, consider transfusion, platelet transfusion if life-threateningESC Bleeding Management Guidelines, 2020
References
- FDA Prescribing Information. Plavix (clopidogrel), Brilinta (ticagrelor), Effient (prasugrel), aspirin. U.S. Food and Drug Administration. https://www.accessdata.fda.gov/scripts/cder/daf/
- Al-Khatib SM, et al. 2023 ACC/AHA Guideline for the Management of Patients With ST-Elevation Myocardial Infarction. Journal of the American College of Cardiology. 2023. https://www.acc.org/guidelines
- Amsterdam EA, et al. 2024 ACC/AHA Guideline for the Management of NSTEMI. Journal of the American College of Cardiology. 2024. https://www.acc.org/guidelines
- Collet JP, et al. ESC Guidelines for ACS without Persistent ST-Segment Elevation. European Heart Journal. 2021;42:1289-1367. https://www.escardio.org/Guidelines
- Wiviott SD, et al. Prasugrel versus Clopidogrel for ACS (TRITON-TIMI 38 Trial). New England Journal of Medicine. 2007;357:2001-2015. https://pubmed.ncbi.nlm.nih.gov/17898643/
- Wallentin L, et al. Ticagrelor versus Clopidogrel in ACS (PLATO Trial). New England Journal of Medicine. 2009;361:1045-1057. https://pubmed.ncbi.nlm.nih.gov/19717846/
- CAPRIE Steering Committee. A Randomized Comparison of Clopidogrel vs Aspirin (CAPRIE Trial). New England Journal of Medicine. 1996;384:947-953. https://pubmed.ncbi.nlm.nih.gov/8618449/
- Kernan WN, et al. AHA/ASA Guideline for the Prevention of Stroke in Patients with Stroke and TIA. Stroke. 2021;52:e364-e467. https://www.strokeassociation.org/
- Valgimigli M, et al. ESC Focused Update on DAPT. European Heart Journal. 2021;42:2648-2678. https://www.escardio.org/Guidelines
- Fröhlich GM, et al. CYP2C19 Genetic Testing and Clopidogrel. Circulation: Genomic and Precision Medicine. 2019;12:e002681. https://www.ahajournals.org/journal/circgen
Medical Disclaimer: This content is for educational purposes only and is not a substitute for professional medical advice. Always consult your healthcare provider before starting, stopping, or changing any medication.
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⚠️ Safety Disclaimer
This information is for educational purposes only and does not constitute medical advice. Always consult your healthcare provider before making any changes to your medication regimen. Dosages and recommendations may vary based on individual health factors.