Can Disprin 325 mg Be Chewed for Myocardial Infarction?
Yes, a 325 mg Disprin (aspirin) tablet should absolutely be chewed immediately in suspected myocardial infarction, as this is the fastest and most effective method to achieve rapid antiplatelet effect.
Recommended Dose and Administration
Administer 162-325 mg of non-enteric-coated aspirin, chewed immediately, to all patients with suspected acute coronary syndrome unless contraindicated. 1, 2, 3
The 325 mg dose falls within the guideline-recommended range and is explicitly supported by the American Heart Association for acute MI. 1
Chewing the tablet is critical—it accelerates absorption and shortens the time to achieve antiplatelet effect compared to swallowing whole. 1, 2, 4
Evidence Supporting Chewing vs. Swallowing
Chewing aspirin achieves 50% platelet inhibition in 5 minutes versus 12 minutes when swallowed whole—a clinically significant difference in acute MI where every minute matters. 4
Chewable aspirin formulations achieve measurable salicylate levels in all patients by 45 minutes, whereas 6 out of 14 patients had no measurable levels at 60 minutes when tablets were swallowed whole. 5
Non-enteric-coated formulations provide more rapid buccal absorption than enteric-coated preparations, which is why guidelines specifically recommend non-enteric formulations for acute presentation. 1, 3
Timing and Clinical Context
Aspirin should be administered as soon as possible after symptom onset—ideally in the prehospital setting by EMS or even by the patient while awaiting EMS arrival. 1, 2
Emergency dispatchers can instruct patients to chew aspirin (160-325 mg) while awaiting ambulance arrival, provided no contraindications exist. 1, 3
The ISIS-2 trial demonstrated a 23% reduction in 5-week vascular mortality when aspirin was administered within 24 hours of acute MI, with earlier administration associated with better outcomes. 2, 6
Absolute Contraindications
Do not administer aspirin if any of the following are present: 1, 3
- Known aspirin allergy or hypersensitivity
- Active gastrointestinal bleeding
- Recent gastrointestinal bleeding (within days to weeks)
- Signs of active bleeding or bleeding diathesis
Practical Algorithm for Aspirin Administration
Step 1: Activate EMS immediately (call 9-1-1) for any patient with suspected cardiac chest pain. 1, 2
Step 2: While awaiting EMS, rapidly assess for contraindications (aspirin allergy, active bleeding). 1, 3
Step 3: If no contraindications exist, give 162-325 mg non-enteric-coated aspirin and instruct the patient to chew thoroughly before swallowing. 1, 2, 3
Step 4: If aspirin has already been given before EMS arrival, inform EMS personnel to avoid duplicate dosing. 1
Common Pitfalls to Avoid
Never use enteric-coated aspirin for acute MI—it significantly delays absorption during the critical early phase when rapid antiplatelet effect is most needed. 1, 3
Do not instruct patients to swallow the tablet whole—this delays the antiplatelet effect by 5-7 minutes compared to chewing, which is critical time lost in acute MI. 2, 3, 4
Never delay EMS activation to give aspirin—call 9-1-1 first, then give aspirin while waiting, as time to treatment directly correlates with mortality reduction. 1, 3
Do not give aspirin to patients with recent bleeding even if cardiac symptoms are severe—mortality from rebleeding can equal or exceed cardiac mortality in this population. 3
Special Considerations
For patients with a remote history of gastrointestinal bleeding (not active or recent), aspirin should still be given immediately, but a proton pump inhibitor must be started simultaneously and continued indefinitely. 3
If the patient cannot take oral aspirin due to severe nausea or vomiting, a 325 mg rectal suppository is an acceptable alternative. 2
For patients with true aspirin allergy, clopidogrel 300 mg orally is the recommended alternative antiplatelet agent. 3