Aspirin Suppository Dose for STEMI
For STEMI patients unable to take oral aspirin, administer 300-500 mg aspirin via rectal suppository as the loading dose, based on the European Society of Cardiology's recommendation for equivalent dosing when oral administration is not possible. 1
Rationale for Suppository Dosing
The standard approach for STEMI is oral aspirin 162-325 mg (chewable, non-enteric coated) given immediately upon diagnosis. 2, 3 However, when oral administration is contraindicated or impossible (e.g., severe nausea, vomiting, altered mental status, intubation), rectal administration provides an alternative route.
The European Society of Cardiology explicitly recommends 250-500 mg IV aspirin when oral administration is not possible, and this same dose range (300-500 mg) can be extrapolated to rectal suppository administration as an alternative parenteral route. 1
Key Dosing Considerations
Loading dose via suppository should be 300-500 mg to achieve rapid antiplatelet effects comparable to oral loading doses of 162-325 mg 1
The higher end of this range (500 mg) may be preferable initially given potentially slower absorption via rectal route compared to chewed oral tablets 2
Avoid excessive dosing: Research demonstrates that initial aspirin doses of 325 mg versus 162 mg showed no mortality benefit, but the higher dose was associated with significantly increased bleeding risk (OR 1.14, p=0.003) 4
Transition to Maintenance Therapy
Once the patient can tolerate oral medications:
Switch to oral aspirin 75-162 mg daily for indefinite maintenance therapy 2
The American College of Cardiology recommends 81 mg daily as the preferred maintenance dose after the acute period 2
For post-PCI patients with stents, higher doses (162-325 mg daily) are recommended for 1-6 months depending on stent type, then reduced to 75-162 mg indefinitely 2
Critical Caveats
Rectal administration is not the preferred route and should only be used when oral administration is truly impossible. 2, 3 The ACC/AHA guidelines emphasize chewable, non-enteric coated oral aspirin for optimal buccal absorption and rapid antiplatelet effect. 2
Do not delay reperfusion therapy while attempting alternative aspirin routes. 3 If suppository placement would cause significant delay, proceed with primary PCI and administer IV aspirin (250-500 mg) instead if available. 1
Absorption kinetics via rectal route are less predictable than oral administration, so clinical monitoring for adequate antiplatelet effect is essential, particularly if the patient requires urgent PCI. 2
Intravenous aspirin (250-500 mg) remains preferable to rectal administration when oral route is unavailable, as IV provides more predictable pharmacokinetics. 1 However, when neither oral nor IV routes are immediately available, rectal suppository at 300-500 mg represents a reasonable alternative to ensure the patient receives this critical Class I therapy without delay. 2, 3