What medications should I prescribe to a patient diagnosed with Acute Coronary Syndrome (ACS)?

Acute Coronary Syndrome Medication Management

All patients with ACS require immediate dual antiplatelet therapy (aspirin plus a P2Y12 inhibitor), parenteral anticoagulation, high-intensity statin therapy, beta-blockers, and ACE inhibitors or ARBs, with additional therapies tailored to specific clinical scenarios. 1

Immediate Antiplatelet Therapy (Start Within Minutes of Diagnosis)

Aspirin - Universal First-Line Agent

• Loading dose: 162-325 mg orally (chewed, non-enteric coated) immediately upon presentation 1
• Maintenance dose: 75-100 mg daily (non-enteric coated) indefinitely 1
• Administer loading dose even if patient already takes daily aspirin 1
• If oral route unavailable, use rectal or intravenous administration 1
• Never exceed 100 mg daily when using ticagrelor due to reduced efficacy at higher aspirin doses 1

P2Y12 Inhibitor Selection - Choose Based on Clinical Scenario

For STEMI or NSTE-ACS undergoing PCI (preferred agents):

• Ticagrelor (first-line choice): Loading dose 180 mg orally, then 90 mg twice daily 1, 2

  • Use regardless of prior P2Y12 inhibitor therapy 1
  • No dose adjustment needed for age or weight 1

• Prasugrel (alternative for PCI patients): Loading dose 60 mg orally, then 10 mg daily 1, 2

  • Reduce to 5 mg daily if age ≥75 years OR body weight <60 kg 1, 2, 3
  • Contraindicated if prior stroke or TIA (increased cerebrovascular events: 6.5% vs 1.2% with clopidogrel) 1, 3, 4
  • Generally avoid in patients ≥75 years except high-risk situations (diabetes or prior MI) 3

For NSTE-ACS with delayed or no PCI planned:

• Clopidogrel: Loading dose 300-600 mg orally, then 75 mg daily 1
  • Use only when prasugrel or ticagrelor unavailable, not tolerated, or contraindicated 1
  • Less potent: 30-40% high on-treatment platelet reactivity vs 3% with newer agents 4

For STEMI receiving fibrinolytic therapy:

• Clopidogrel: 300 mg loading dose if age ≤75 years; 75 mg initial dose if age >75 years, then 75 mg daily 1
  • Administer concurrently with fibrinolytic 1

Duration: Continue dual antiplatelet therapy for 12 months unless excessive bleeding risk 1, 2

Parenteral Anticoagulation (Start Immediately)

For Medical Management (No Immediate PCI)

• Fondaparinux (preferred): 2.5 mg subcutaneously daily 2

  • Contraindicated if creatinine clearance <30 mL/min 2

• Enoxaparin (alternative): 1 mg/kg subcutaneously every 12 hours 2

  • Reduce to 1 mg/kg daily if creatinine clearance <30 mL/min 2

• Unfractionated heparin (alternative): Standard weight-based dosing 1

For PCI Support

• Bivalirudin: 0.75 mg/kg IV bolus, then 1.75 mg/kg/hour infusion during PCI 1, 2

• Unfractionated heparin: 85 IU/kg bolus (60 IU/kg if using GP IIb/IIIa inhibitors) 1

• If patient on fondaparinux, add single UFH bolus (85 IU/kg) at time of PCI 1

Discontinue parenteral anticoagulation immediately after invasive procedure 1

High-Intensity Statin Therapy (Start Immediately)

• Atorvastatin 80 mg daily OR rosuvastatin 40 mg daily 2, 5
• Initiate immediately regardless of baseline lipid levels 2
• Continue indefinitely for secondary prevention 2, 5

Beta-Blockers (Start Within 24 Hours)

• Initiate early in patients with ongoing ischemic symptoms, hypertension, or tachycardia 2
• Essential for reducing morbidity and mortality, particularly with LV dysfunction 2
• Avoid in acute decompensated heart failure, cardiogenic shock, or high-degree AV block 2

ACE Inhibitors or ARBs (Start Within 24 Hours)

• ACE inhibitor (preferred): Start low dose, titrate upward 2, 5
• ARB if ACE inhibitor not tolerated (e.g., cough) 2, 5
• Particularly important if heart failure, hypertension, diabetes, or LV dysfunction present 2, 5

Symptom Management

For Chest Pain

• Sublingual nitroglycerin: 0.4 mg every 5 minutes up to 3 doses 1

• IV nitroglycerin: 5-10 mcg/min, titrate to effect if pain persists 1

  • Contraindications: SBP <90 mm Hg, suspected RV infarction, PDE5 inhibitor use within 12 hours (avanafil), 24 hours (sildenafil/vardenafil), or 48 hours (tadalafil) 1

• Morphine: 2-4 mg IV, repeat every 5-15 minutes if needed (up to 10 mg total) 1

  • Use only for pain resistant to maximally tolerated anti-ischemic medications 1
  • May delay absorption of oral P2Y12 inhibitors 1

• Avoid NSAIDs - associated with increased MACE risk without documented benefit 1

Gastrointestinal Protection

• Proton pump inhibitor for patients at increased GI bleeding risk: 2, 5
  • Age >70 years, history of GI bleeding, concurrent anticoagulation, or NSAID use 6
  • Avoid omeprazole or esomeprazole with clopidogrel (significantly reduces antiplatelet activity) 7

Special Considerations

Patients Requiring Oral Anticoagulation

• Prefer direct oral anticoagulant (DOAC) over warfarin 2, 5
• After 1-4 weeks post-PCI, discontinue aspirin and continue P2Y12 inhibitor plus anticoagulant 1

Renal Impairment

• Adjust anticoagulant doses based on creatinine clearance 2
• Fondaparinux contraindicated if CrCl <30 mL/min 2
• Enoxaparin reduced to 1 mg/kg daily if CrCl <30 mL/min 2

Aspirin Hypersensitivity

• Aspirin desensitization preferred whenever possible 1
• If desensitization not feasible, use P2Y12 inhibitor monotherapy 1

Common Pitfalls to Avoid

• Do not delay P2Y12 inhibitor loading dose - benefits emerge rapidly after loading 8
• Do not use prasugrel before coronary anatomy known in NSTE-ACS (increased bleeding risk if urgent CABG needed) 1, 3
• Do not use high-dose aspirin (>100 mg) with ticagrelor 1
• Do not cross over between UFH and LMWH 1
• Do not continue full-dose aspirin (300-325 mg) beyond initial loading - associated with increased bleeding without additional benefit 1