What are the proper usage and precautions for taking Aspirin (acetylsalicylic acid) 325?

Proper Usage and Precautions for Aspirin 325 mg

Aspirin 325 mg should be administered as a non-enteric-coated, chewable tablet for immediate absorption in acute coronary syndromes, with a maintenance dose of 81-325 mg daily for long-term cardiovascular prevention, while monitoring for gastrointestinal bleeding and avoiding use in patients with aspirin allergy, active bleeding, or concurrent PDE-5 inhibitor use. 1

Indications for Aspirin 325 mg

• Aspirin 325 mg is indicated for acute coronary syndromes (ACS) including ST-elevation myocardial infarction (STEMI) and non-ST-elevation acute coronary syndromes (NSTE-ACS) 1
• It is used for secondary prevention in patients with established cardiovascular disease, including those with prior myocardial infarction, stroke, or peripheral artery disease 1, 2
• The initial dose for suspected ACS should be 162-325 mg, administered as a non-enteric-coated, chewable tablet for more rapid absorption 1

Dosing Recommendations

• For acute coronary syndromes, emergency medical services (EMS) providers should administer 160-325 mg non-enteric-coated aspirin to be chewed by the patient 1
• For long-term maintenance therapy after ACS or for secondary prevention, doses ranging from 81-325 mg daily are effective 1
• For patients with peripheral artery disease, 75-325 mg daily is recommended to reduce risk of cardiovascular events 1
• Non-enteric-coated formulations are preferred for initial dosing due to more rapid buccal absorption compared to enteric-coated versions 1

Administration Considerations

• Chewing the aspirin tablet hastens absorption, which is critical in acute settings 1
• For patients unable to take oral medications, aspirin suppositories (300 mg) can be considered in cases of severe nausea, vomiting, or upper gastrointestinal disorders 1
• After percutaneous coronary intervention (PCI), it is reasonable to use 81 mg daily aspirin in preference to higher maintenance doses 1
• When used with ticagrelor, the recommended maintenance dose of aspirin is 81 mg daily 1

Contraindications and Precautions

• Aspirin is contraindicated in patients with:

  • Known aspirin allergy or hypersensitivity 1
  • Active or recent gastrointestinal bleeding 1
  • Hemophilia or other bleeding disorders 3
  • Concurrent use of PDE-5 inhibitors (within 24 hours, or 48 hours for tadalafil) 1

• Use aspirin with caution in patients with:

  • History of peptic ulcer disease 3
  • Concurrent anticoagulant therapy 3
  • Severe renal or hepatic impairment 3
  • Asthma (due to risk of aspirin-exacerbated respiratory disease) 1

Special Populations

• For patients with aspirin allergy:

  • Consider clopidogrel as an alternative antiplatelet agent 1
  • For patients requiring aspirin despite history of hypersensitivity, a graded challenge protocol may be used 1
  • A two-step challenge protocol (starting with 40.5 mg) can be efficient for patients with remote history of NSAID reaction without aspirin-exacerbated respiratory disease 1

• For patients at high risk of gastrointestinal complications:

  • Consider co-therapy with proton pump inhibitors 4
  • Coordinated-delivery tablets combining enteric-coated aspirin with immediate-release omeprazole may improve adherence and reduce GI events 4

Monitoring and Safety

• Monitor for signs of bleeding, particularly gastrointestinal bleeding 1, 2
• The risk of major bleeding with 160 mg/day is approximately 1-2 cases per 1000 patient-years of treatment 5
• High-dose aspirin (≥160 mg) versus low-dose (<160 mg) is associated with increased bleeding risk 1
• Most NSAIDs can interfere with the antiplatelet effects of aspirin and should be avoided when possible 1

Duration of Therapy

• For patients with ACS treated with stent implantation, aspirin should be continued indefinitely 1
• Dual antiplatelet therapy (aspirin plus P2Y12 inhibitor) is typically recommended for up to 12 months after ACS 1
• For secondary prevention, aspirin therapy is generally continued indefinitely unless contraindications develop 1, 2