What is the recommended first aid tablet for Myocardial Infarction (MI)?

First Aid Tablet for Myocardial Infarction

Aspirin 162-325 mg (chewed and swallowed) is the recommended first aid tablet for suspected myocardial infarction, administered while awaiting emergency medical services arrival. 1

Immediate Action Algorithm

Step 1: Activate Emergency Medical Services First

• Call 911 immediately before administering any medication - this is the priority action for anyone experiencing chest pain or MI symptoms 1
• EMS transportation reduces ischemic time and treatment delays compared to private vehicle transport, and approximately 1 in 300 patients with chest pain transported by private vehicle experiences cardiac arrest en route 1

Step 2: Aspirin Administration While Awaiting EMS

Dosing:

• Administer 162-325 mg of non-enteric coated aspirin (chewed and swallowed) 1
• The patient should chew the aspirin to ensure rapid absorption 1
• Both 162 mg and 325 mg doses are effective, though 162 mg may have a slightly better bleeding safety profile 2

Contraindications - Do NOT give aspirin if:

• Known aspirin allergy 1
• Recent bleeding episode 1
• Patient has been specifically advised by a healthcare professional not to take aspirin 1
• Any uncertainty exists about whether aspirin should be given 1

Step 3: If Uncertain, Wait for EMS

If there is any doubt about contraindications, it is reasonable to wait for EMS arrival without administering aspirin 1

Evidence Supporting Aspirin as First Aid

Mortality Benefit

• Early aspirin administration (median 1.6 hours from pain onset) demonstrates higher survival rates compared to late administration (median 3.5 hours) at 7 days, 30 days, and 1 year 1, 3
• Aspirin given within the first 24 hours after acute MI resulted in a 23% relative risk reduction in 5-week vascular mortality 1
• Self-administration of aspirin within 4 hours of severe chest pain onset could delay approximately 13,000 deaths annually in the United States 4

Safety Profile

• The rate of major complications from a single aspirin dose in individuals experiencing chest pain is low 1
• Two observational studies with 2,122 patients found no significant difference in complication risk between early versus late aspirin administration 1

What NOT to Give as First Aid

Nitroglycerin is NOT Recommended for First Aid

• Nitroglycerin sublingual tablets are contraindicated in early myocardial infarction per FDA labeling 5
• The benefits of sublingual nitroglycerin in acute MI have not been established, and it carries risk of hypotension and tachycardia 5
• Nitroglycerin is absolutely contraindicated if the patient has taken phosphodiesterase-5 inhibitors (sildenafil, tadalafil, vardenafil) within 48 hours due to risk of severe, potentially fatal hypotension 5, 6

Oxygen is NOT Routinely Recommended

• There is no evidence supporting routine oxygen administration as a first aid measure for chest pain 1
• The American Heart Association does not recommend oxygen administration in healthcare settings for acute coronary syndromes in non-hypoxic patients 1

Common Pitfalls to Avoid

1. Delaying EMS activation to give aspirin - Always activate EMS first 1
2. Giving enteric-coated aspirin - Use non-enteric coated formulation for faster absorption 1
3. Administering aspirin when contraindications exist - When in doubt, wait for EMS 1
4. Using nitroglycerin as first aid - This is contraindicated in early MI and with recent PDE-5 inhibitor use 5
5. Giving higher doses assuming better efficacy - 162 mg is as effective as 325 mg with potentially less bleeding risk 2