What is the recommended medication regimen for acute coronary syndrome?

Acute Coronary Syndrome Medication Regimen

All patients with acute coronary syndrome must receive dual antiplatelet therapy (aspirin plus a P2Y12 inhibitor) combined with anticoagulation, a statin, and a proton pump inhibitor immediately upon diagnosis. 1

Immediate Antiplatelet Therapy

Aspirin

• Administer aspirin 162–325 mg orally (chewed, non-enteric coated) as the loading dose immediately upon ACS diagnosis, followed by 75–100 mg daily maintenance. 1
• If the patient cannot take oral medication, use rectal or intravenous aspirin. 1

P2Y12 Inhibitor Selection

First-line: Ticagrelor

• Give ticagrelor 180 mg loading dose orally immediately after ACS diagnosis (before any invasive procedure), then 90 mg twice daily for 12 months. 1, 2
• Ticagrelor is preferred over clopidogrel because it reduces cardiovascular death, myocardial infarction, stroke, and stent thrombosis. 2, 3
• Never exceed 100 mg daily aspirin when combined with ticagrelor—higher doses blunt ticagrelor's antiplatelet effect (FDA black-box warning). 1, 2

Second-line: Prasugrel

• Use prasugrel 60 mg loading dose followed by 10 mg daily only for P2Y12-naïve patients undergoing PCI, and only after coronary anatomy is defined by angiography. 1, 2
• Absolute contraindication: Never give prasugrel to any patient with prior stroke or TIA, regardless of how remote the event—this increases cerebrovascular bleeding (6.5% vs 1.2% with clopidogrel). 1, 2, 4
• Reduce maintenance dose to 5 mg daily if body weight <60 kg or age ≥75 years. 1

Third-line: Clopidogrel

• Reserve clopidogrel 600 mg loading dose followed by 75 mg daily only when ticagrelor and prasugrel are unavailable, contraindicated, or when oral anticoagulation is required (triple therapy). 1, 2, 3
• For STEMI managed with fibrinolysis, use clopidogrel 300 mg loading (75 mg if age >75 years), then 75 mg daily. 1

Anticoagulation (Mandatory for All ACS Patients)

• All ACS patients require parenteral anticoagulation in addition to dual antiplatelet therapy, regardless of management strategy. 3, 5
• Options include unfractionated heparin, enoxaparin, bivalirudin, or fondaparinux. 3, 5

Statin Therapy

• Initiate high-intensity statin therapy immediately at ACS diagnosis, typically combined with ezetimibe for faster LDL-C reduction. 6, 7

Bleeding Risk Mitigation (Class I Recommendations)

• Prescribe a proton pump inhibitor (pantoprazole 40 mg daily preferred) to every patient on dual antiplatelet therapy—this is mandatory, not optional. 1, 2, 3
• Pantoprazole has the lowest CYP2C19 inhibition and does not attenuate clopidogrel efficacy. 2
• Use radial artery access (not femoral) for PCI when performed by an experienced radial operator. 1, 2

Duration of Dual Antiplatelet Therapy

• Standard duration is 12 months for all ACS patients (STEMI, NSTEMI, unstable angina), regardless of stent type, management strategy (PCI, medical therapy, or CABG), or completeness of revascularization. 1, 2, 3
• Shorten to 6 months only if PRECISE-DAPT score ≥25 (high bleeding risk). 1, 2

Additional Therapies

• Beta blockers, ACE inhibitors (or ARBs), nitroglycerin for chest pain relief, and oxygen (if hypoxic) should be initiated. 5, 8
• Morphine 2–4 mg IV may be used for pain resistant to maximally tolerated anti-ischemic medications, but it may delay oral P2Y12 inhibitor absorption. 1

Critical Pitfalls to Avoid

• Never discontinue dual antiplatelet therapy within the first 30 days after stent placement—this dramatically increases stent thrombosis, myocardial infarction, and death risk. 1, 2, 3
• Never omit the proton pump inhibitor—this simple intervention significantly reduces gastrointestinal bleeding. 1, 2, 3
• Never use clopidogrel as first-line therapy when ticagrelor is available and not contraindicated—this represents suboptimal care. 2, 3
• Never give prasugrel before coronary anatomy is known by angiography. 1, 2
• Never use ticagrelor or prasugrel in patients requiring oral anticoagulation (triple therapy)—switch to clopidogrel due to substantially lower bleeding risk. 2, 9

Special Scenarios

If patient requires oral anticoagulation:

• Limit triple therapy (OAC + aspirin + clopidogrel) to maximum 1 month, then transition to dual therapy (OAC + clopidogrel) for up to 12 months. 9
• Use clopidogrel (not ticagrelor or prasugrel) as the P2Y12 inhibitor. 2, 9
• Use lowest effective NOAC dose (e.g., rivaroxaban 15 mg daily instead of 20 mg). 9

If patient has prior stroke/TIA:

• Use ticagrelor (not prasugrel—absolute contraindication). 2
• If ticagrelor unavailable or not tolerated, use clopidogrel. 2

If patient requires CABG:

• Stop ticagrelor or clopidogrel ≥5 days before surgery; stop prasugrel ≥7 days before surgery. 2
• Resume P2Y12 inhibitor after CABG to complete 12 months of dual antiplatelet therapy. 2, 3