Back to Course

Emergency Medicine: Cardiology 213

0% Complete
0/0 Steps
  1. Acute Coronary Syndromes: A Focus on STEMI
    10 Topics
    3 Quizzes
  2. Acute decompensated heart failure
    10 Topics
    3 Quizzes
  3. Hypertensive Urgency and Emergency Management
    11 Topics
    3 Quizzes
  4. Acute aortic dissection
    9 Topics
    2 Quizzes
  5. Arrhythmias (Afib, SVT, VTach)
    10 Topics
    2 Quizzes

Participants 206

  • April
  • Alyssa
  • Ashley
  • Amber
  • Sherif
Show more
Lesson Progress
0% Complete


Aspirin in Antiplatelet Therapy for ACS

  • Aspirin is an anti-platelet agent used to reduce the risk of thrombus formation in Acute Coronary Syndrome (ACS)
  • Mechanism of Action: Aspirin irreversibly inhibits cyclooxygenase (COX) enzymes, resulting in decreased synthesis of thromboxane A2, which plays a key role in platelet aggregation
Antiplatelet- COX2 Inhibition162-325 mg/day30 minutesHypersensitivity to aspirin, bleeding disorders, active bleeding, recent surgery, severe thrombocytopenia

AHA STEMI Guidelines- Aspirin Prior to PCI

DrugRecommended DosageIndicationCORLOE
Aspirin162- to 325-mg loadBefore procedureIB
81- to 325-mg dailyMaintenance dose (indefinite)IA
81 mg daily is preferredMaintenance dose (indefinite)IIaB

2013 ACCF/AHA guideline. Circulation. 2013 Jan 29;127(4):e362-425.



  • Mechanism of Action:
    • Irreversibly Inhibits ADP-induced platelet aggregation by blocking the binding of ADP to its receptor
  • Dosage:
    • 60 mg orally once daily; 10 mg for patients of 75 years and older
  • Pharmacokinetics:
    • Rapidly absorbed with peak plasma concentrations within 1 hour of administration
  • Adverse Effects:
    • Bleeding, headache, nausea, diarrhea, dyspnea
  • Contraindications:
    • Active pathological bleeding, prior stroke, severe hepatic failure
  • Clinical Pearls:
    • Take with or without food; dose adjustment needed with strong CYP3A4 inhibitors
  • Practical Considerations:
    • Not recommended in patients ≥75 years of age
    • Prasugrel is contraindicated in patients with a history of stroke or transient ischemic attack (TIA), as it has been associated with an increased risk of bleeding in these patients.
    • Prasugrel should be discontinued at least 7 days prior to elective surgery or dental procedures to minimize the risk of bleeding.



  • Mechanism of action:
    • Reversibly binds to P2Y12 receptor on platelets and inhibits the ADP-mediated platelet activation and aggregation
  • Dosage:
    • Loading dose: 30 mcg/kg IV bolus
    • Maintenance dose: 4 mcg/kg/min IV infusion
    • Duration of infusion: Until the end of the PCI procedure
  • PK:
    • Onset of action: Within 2 minutes of bolus administration
    • Elimination half-life: 3 to 6 minutes
    • Platelet function returns to baseline within 1 hour of discontinuation
  • Adverse Effects:
    • Dyspnea, hypotension, headache, bleeding
  • Clinical Pearls & Practical Considerations:
    • Discontinue 1 hour prior to CABG surgery to reduce bleeding risk
    • May be useful in patients who cannot tolerate oral P2Y12 inhibitors due to dysphagia or malabsorption

Antiplatelet Drug Chart

DrugProdrug?Loading DoseMaintenance DoseDiscontinue Prior to Surgery/Dental Procedures
ClopidogrelYes300-600 mg75 mg daily5 days
PrasugrelNo60 mg10 mg daily7-10 days
TicagrelorNo180 mg90 mg twice daily5 days
CangrelorNo30 mcg/kg/min for 4 minutes, then 4 mcg/kg/minN/A (IV infusion only)N/A

AHA STEMI Guidelines- P2Y12 Inhibitors Prior to PCI

ClopidogrelLoading dose 600mg early or at time of PCIIB
Maintenance dose: 75mg dailyIB
Duration: Continue for 1 year (DES or BMS)IB
Continued beyond 1 y when DES placedIIIB
PrasugrelLoading dose 60mg early or at time of PCIIB
Maintenance dose: 10mg dailyIB
Duration: Continue for 1 year (DES or BMS)IB
Contraindicated (patients with STEMI and prior stroke or TIA)IIIB
Continued beyond 1 y when DES placedIII (harm)B
TicagrelorLoading dose 180mg early or at time of PCIIB
Maintenance dose: 90mg twice dailyIB
Duration: Continue for 1 year (DES or BMS)IB

ESC STEMI Guidelines: Antiplatelet Therapy

A potent P2Y12 inhibitor (prasugrel or ticagrelor), or clopidogrel if these are not available or are contraindicated, is recommended before (or at least at the time of) PCI and maintained over 12 months unless there are contraindications such as excessive risk of bleeding.IA
Aspirin (oral or IV, if unable to swallow) is recommended as soon as possible for all patients without contraindications.IB
Cangrelor may be considered in patients who have not received P2Y12 receptor inhibitors.IIbA