What medications can be given to a patient with ST-Elevation Myocardial Infarction (STEMI) who refuses catheterization, according to the latest guidelines?

Medical Management of STEMI When Catheterization is Refused

For a STEMI patient refusing catheterization, immediate fibrinolytic therapy should be initiated within 30 minutes of diagnosis using a fibrin-specific agent (tenecteplase, alteplase, or reteplase), combined with mandatory dual antiplatelet therapy (aspirin plus clopidogrel) and anticoagulation (preferably enoxaparin). 1, 2

Fibrinolytic Therapy (Primary Reperfusion)

Fibrin-specific agents are strongly preferred over streptokinase:

• Tenecteplase (TNK-tPA): Single weight-based IV bolus over 5 seconds 2, 3

  • <60 kg: 30 mg
  • 60-69 kg: 35 mg
  • 70-79 kg: 40 mg
  • 80-89 kg: 45 mg
  • ≥90 kg: 50 mg
  • For patients ≥75 years, consider half-dose to reduce bleeding risk 2

• Alteplase (tPA): Three-phase infusion 3

  • 15 mg IV bolus
  • 0.75 mg/kg over 30 minutes (maximum 50 mg)
  • 0.5 mg/kg over 60 minutes (maximum 35 mg)

• Reteplase: Double bolus regimen 3

  • 10 units IV bolus
  • Second 10 units IV bolus 30 minutes later

Critical timing: Initiate within 30 minutes of STEMI diagnosis, ideally within 12 hours of symptom onset (greatest benefit within first 6 hours) 1, 2, 3

Mandatory Antiplatelet Therapy

Aspirin (Class I, Level A)

• Loading dose: 162-325 mg orally (chewable, non-enteric coated) OR 250-500 mg IV if unable to swallow 1, 3
• Maintenance: 75-100 mg daily indefinitely 1, 4

Clopidogrel (Class I, Level A)

Age-based loading dose: 1, 3

• ≤75 years: 300 mg loading dose
• >75 years: 75 mg loading dose (no bolus)

Maintenance: 75 mg daily for minimum 14 days, ideally up to 12 months 1, 2, 3, 5

Important caveat: Clopidogrel is the mandatory P2Y12 inhibitor choice in fibrinolytic therapy (prasugrel is contraindicated with fibrinolytics) 1

Mandatory Anticoagulation (Class I)

Enoxaparin (Preferred over UFH)

Age and renal-adjusted dosing: 1, 2, 3

• <75 years with normal renal function:

  • 30 mg IV bolus
  • Then 1 mg/kg subcutaneous every 12 hours (maximum 100 mg for first 2 doses)

• ≥75 years:

  • No IV bolus
  • 0.75 mg/kg subcutaneous every 12 hours (maximum 75 mg for first 2 doses)

• Renal impairment (CrCl <30 mL/min): 1 mg/kg subcutaneous once daily

Duration: Minimum 48 hours, preferably until revascularization or up to 8 days of hospitalization 1, 2, 3

Unfractionated Heparin (Alternative)

• Weight-adjusted IV bolus: 60 units/kg (maximum 4000 units) 1
• Infusion: 12 units/kg/hour (maximum 1000 units/hour)
• Target aPTT: 50-70 seconds (1.5-2 times control) 1

Critical warning: Fondaparinux should NOT be used as sole anticoagulation if subsequent PCI is planned (increases catheter thrombosis risk) 1, 2

Additional Essential Medications

ACE Inhibitors (Class I, Level A)

Initiate within first 24 hours (after blood pressure stabilizes): 1, 4

• Indications for mandatory use:
  • Anterior infarction
  • Pulmonary congestion/heart failure
  • LVEF <40%
  • Systolic BP ≥100 mmHg (or not >30 mmHg below baseline)

Starting doses (titrate upward):

• Lisinopril: 2.5-5 mg daily
• Ramipril: 2.5 mg daily
• Captopril: 6.25 mg three times daily

Alternative: ARB (valsartan or candesartan) if ACE inhibitor intolerant 1

Beta-Blockers (Class I)

Initiate within 24 hours if no contraindications: 4

• Metoprolol: 25-50 mg twice daily (or 50-100 mg extended-release daily)
• Carvedilol: 3.125-6.25 mg twice daily
• Bisoprolol: 2.5-5 mg daily

Contraindications: Heart failure signs, evidence of low output state, increased risk for cardiogenic shock, PR interval >0.24 seconds, second or third-degree heart block, active asthma/reactive airway disease 4

High-Intensity Statin (Class I)

Initiate as early as possible: 4

• Atorvastatin: 80 mg daily
• Rosuvastatin: 20-40 mg daily

Target: LDL-C <70 mg/dL or ≥50% reduction from baseline 4

Critical Post-Fibrinolysis Management

All patients must be transferred immediately to PCI-capable center after fibrinolysis 1, 2

Assess Reperfusion Success at 60-90 Minutes

Rescue PCI indicated immediately if: 1, 2

• <50% ST-segment resolution
• Hemodynamic instability or cardiogenic shock
• Electrical instability (ventricular arrhythmias)
• Worsening ischemia or evidence of reocclusion

Routine Angiography Timing

If fibrinolysis successful: Perform angiography and PCI (if indicated) between 2-24 hours after fibrinolysis 1, 2

Common Pitfalls to Avoid

1. Never use prasugrel or ticagrelor with fibrinolytic therapy - only clopidogrel is appropriate 1

2. Do not use IV ACE inhibitors in first 24 hours - risk of hypotension (use oral formulations) 1

3. Avoid fondaparinux as sole anticoagulant if any possibility of subsequent PCI 1, 2

4. Do not delay fibrinolysis waiting for laboratory results - decision based on ECG and clinical presentation only 1, 2

5. Weight-adjusted anticoagulation is essential - fixed-dose heparin results in subtherapeutic levels in 82% of patients 6

6. Continue dual antiplatelet therapy for 12 months regardless of whether patient eventually undergoes PCI 1