What medications are used to treat chest pain of cardiac origin?

Medications for Chest Pain of Cardiac Origin

For chest pain of cardiac origin, the first-line medications include aspirin (162-325 mg), nitroglycerin, and beta-blockers, with aspirin administration recommended while awaiting EMS arrival for suspected myocardial infarction. 1

Immediate Management of Acute Chest Pain

First Steps

• Activate EMS immediately for anyone with chest pain or other signs of heart attack 1
• While awaiting EMS arrival, first aid providers may encourage alert adults with suspected cardiac chest pain to chew and swallow aspirin (162-325 mg), unless contraindicated by allergy or recent bleeding 1
• If uncertain about aspirin administration, wait for EMS arrival 1

Hospital/Emergency Department Management

1. Aspirin

   • 160-325 mg initially, then continued indefinitely (75-162 mg daily for long-term therapy) 1, 2
   • Early administration (within 2 hours of symptom onset) is associated with improved survival compared to delayed administration 3

2. Nitroglycerin

   • Administered sublingually for acute relief of chest pain
   • Can be infused intravenously for 24-48 hours after hospitalization 1
   • Contraindicated in patients with:
     • Initial systolic BP <90 mmHg or 30 mmHg below baseline
     • Right ventricular infarction
     • Recent use of PDE-5 inhibitors (within 24-48 hours) 1, 4

3. Beta-blockers (e.g., metoprolol)

   • Should be initiated early in patients with evolving acute MI, regardless of whether reperfusion therapy was given 1
   • Administered intravenously initially, then orally 1, 5
   • Contraindicated in patients with hypotension, bradycardia, or signs of heart failure 5

4. Analgesics

   • Intravenous morphine for persistent chest pain in STEMI 1
   • May be considered for undifferentiated chest pain unresponsive to nitroglycerin 1
   • Use with caution in unstable angina/NSTEMI due to association with increased mortality 1

Long-term Management

For indefinite period after acute MI:

• Aspirin (75-160 mg daily) 1, 2
• Beta-blocker 1
• ACE inhibitor 1

Special Considerations

Aspirin Dosing

• Acute setting: 162-325 mg 1
• Long-term prevention: 75-160 mg daily 2
• Higher initial doses may be beneficial in acute coronary syndromes, followed by lower maintenance doses 6

Nitroglycerin Administration

• Should be dissolved under the tongue or in oral cavity at first sign of chest pain
• May be repeated approximately every 5 minutes until pain is relieved
• If pain persists after 3 tablets in 15 minutes, or is different than typical, call for emergency help 4
• May be used 5-10 minutes prior to activities that might cause chest pain 4

Cautions

• Be aware of aspirin-induced chest pain, which can occur through GI irritation or allergic reactions 7
• Calcium channel blockers have not been shown to reduce mortality in acute MI and may be harmful in certain patients 1
• Nitroglycerin should not be used as a substitute for analgesics often required in acute MI 1

Common Pitfalls

• Delaying EMS activation while attempting self-treatment
• Failing to recognize non-classic symptoms of cardiac chest pain, particularly in women, elderly, and diabetic patients
• Using calcium channel blockers as first-line therapy
• Not considering contraindications to aspirin or nitroglycerin before administration
• Administering nitroglycerin to patients with hypotension or recent use of erectile dysfunction medications

Remember that chest pain can have both cardiac and non-cardiac origins, with approximately half of cases being non-cardiac (primarily esophageal disorders) 8. However, all chest pain should be treated as potentially cardiac until proven otherwise.