What is the recommended medication regimen and dosing for management of non‑ST‑segment elevation myocardial infarction (NSTEMI) in an adult patient?

NSTEMI Medication Management and Dosages

All NSTEMI patients should receive immediate dual antiplatelet therapy with aspirin plus a P2Y12 inhibitor, along with anticoagulation, beta-blockers, high-intensity statins, and anti-ischemic therapy as outlined below.

Immediate Antiplatelet Therapy (Class I)

Aspirin

• Loading dose: 162-325 mg non-enteric coated, chewable aspirin immediately on presentation 1, 2
• Maintenance dose: 81 mg daily (preferred) to 325 mg daily indefinitely 1
• Note: When using ticagrelor, aspirin maintenance must be 81 mg daily 1, 2

P2Y12 Inhibitor (choose one based on strategy)

For Early Invasive Strategy (planned catheterization):

Preferred options (in order):

1. Ticagrelor (Class IIa preference over clopidogrel) 1

   • Loading: 180 mg orally
   • Maintenance: 90 mg twice daily for up to 12 months

2. Prasugrel (only at time of PCI, after anatomy known) 1

   • Loading: 60 mg orally
   • Maintenance: 10 mg daily (5 mg if weight <60 kg or age ≥75 years)
   • Contraindicated: History of stroke/TIA 1

3. Clopidogrel (if ticagrelor/prasugrel unavailable or contraindicated) 1

   • Loading: 300-600 mg orally
   • Maintenance: 75 mg daily for up to 12 months

For Conservative/Ischemia-Guided Strategy:

• Clopidogrel 300-600 mg loading, then 75 mg daily, OR
• Ticagrelor 180 mg loading, then 90 mg twice daily 3, 4

Duration: Continue P2Y12 inhibitor for at least 12 months in all patients 1, 4, 1

Anticoagulation (Class I)

Choose ONE anticoagulant and continue until revascularization or hospital discharge (up to 8 days):

1. Enoxaparin: 1 mg/kg subcutaneously every 12 hours 3

   • If PCI: 0.5 mg/kg IV bolus if last dose >8 hours prior

2. Unfractionated Heparin: 60 units/kg IV bolus (max 4000 units), then 12 units/kg/hour infusion (max 1000 units/hour), adjusted to aPTT 1.5-2.5× control 3

3. Fondaparinux: 2.5 mg subcutaneously daily (preferred if high bleeding risk) 3

4. Bivalirudin: 0.75 mg/kg IV bolus, then 1.75 mg/kg/hour infusion 3

Anti-Ischemic Therapy

Nitroglycerin (Class I)

• Sublingual: 0.3-0.4 mg every 5 minutes × 3 doses for ongoing chest pain 5
• IV infusion: Start at 10 mcg/min, titrate by 10 mcg/min every 3-5 minutes for persistent ischemia, heart failure, or hypertension 5
• Contraindication: Recent phosphodiesterase inhibitor use (24 hours for sildenafil/vardenafil, 48 hours for tadalafil) 5

Beta-Blockers (Class I)

• Initiate oral beta-blocker within first 24 hours unless contraindicated (heart failure, low-output state, cardiogenic shock risk) 5
• Options: Metoprolol tartrate 25-50 mg every 6-12 hours, or metoprolol succinate 25-100 mg daily
• Avoid IV beta-blockers if shock risk factors present 5

Morphine (Class IIb)

• 2-4 mg IV for continued ischemic pain despite maximal anti-ischemic therapy, may repeat every 5-15 minutes 5

Cardioprotective Therapy (Class I)

High-Intensity Statin

• Initiate immediately regardless of baseline lipid levels 5, 1
• Atorvastatin 40-80 mg daily OR Rosuvastatin 20-40 mg daily

ACE Inhibitor (Class I for specific indications)

• Start within 24 hours if: anterior MI, heart failure, LVEF <40%, diabetes, or hypertension 1
• Examples: Lisinopril 2.5-5 mg daily initially, titrate to 10-40 mg daily
• ARB if ACE inhibitor not tolerated 1

Aldosterone Antagonist (if indicated)

• Eplerenone 25 mg daily (start 3-14 days post-MI if LVEF <40% and heart failure or diabetes, without significant renal dysfunction or hyperkalemia) 1

Medications to AVOID (Class III: Harm)

• NSAIDs (except aspirin): Discontinue immediately, increased MACE risk 5, 4
• Immediate-release nifedipine without beta-blocker 5
• Prasugrel in patients with prior stroke/TIA 1

GP IIb/IIIa Inhibitors (Selective Use)

Only for high-risk patients (elevated troponin, ongoing ischemia) undergoing invasive strategy 3, 1:

• Eptifibatide: 180 mcg/kg IV bolus × 2 (10 minutes apart), then 2 mcg/kg/min infusion up to 18 hours
• Tirofiban: 25 mcg/kg IV bolus over 3 minutes, then 0.15 mcg/kg/min infusion up to 18 hours

Not recommended as routine upstream triple antiplatelet therapy 3

Critical Timing Considerations

• Aspirin and anticoagulation: Immediately on presentation
• P2Y12 inhibitor: On presentation for invasive strategy; ticagrelor preferred over clopidogrel 1
• Prasugrel: Only after coronary anatomy known at PCI (not for pretreatment) 1
• Beta-blocker: Within 24 hours if no contraindications 5
• Statin: Immediately, preferably within 24 hours 1

Special Populations

If CABG planned: Discontinue clopidogrel 5 days, prasugrel/ticagrelor 7 days before surgery unless urgent 4, 3

Renal dysfunction: No dose adjustment needed for P2Y12 inhibitors; adjust anticoagulation (avoid enoxaparin if CrCl <30 mL/min, use UFH or reduce fondaparinux dose) 6

This evidence-based regimen from the 2014 AHA/ACC guidelines 5, 1 and 2025 ACC/AHA update 2 provides the foundation for reducing mortality and major adverse cardiac events in NSTEMI patients.