Mechanism of action: Aspirin is a more potent inhibitor of both prostaglandin synthesis and platelet aggregation than its other salicylic derivatives due to the acetyl group on the aspirin molecule, which irreversibly inactivates cyclooxygenase via acetylation.

This prevents the conversion of arachidonic acid to thromboxane A. Platelet aggregation is inhibited for their lifespan of 7 to 10 days.

Therapeutic Class: non-opioid analgesic, non-steroidal anti-inflammatory, antipyretic, antiplatelet


  • Cardiovascular disease (secondary prevention)
  • Management of unstable angina and non-ST-segment elevation myocardial infarction (NSTEMI)
  • Management of ST-segment elevation myocardial infarction (STEMI)
  • Suspected transient ischaemic attack
  • Acute ischaemic stroke
  • Atrial fibrillation following a disabling ischaemic stroke
  • Mild to moderate pain

Contraindications: hepatic disease, renal disease, alcoholism, chronic malnutrition, severe hypovolemia

Side Effects; anxiety, headache, dyspnea, hypertension or hypotension, hepatotoxicity, constipation, nausea, vomiting, renal failure (high doses/chronic use), neutropenia, muscle spasms, acute generalized exanthematous pustulosis, stevens- Johnson syndrome, toxic epidermal necrolysis, rash, urticaria


  • Fetal risk cannot be ruled out.


  • Drugs that have been associated with significant effects on some nursing infants and should be given to nursing mothers with caution.
  • WHO: Avoid breastfeeding.
  • Micromedex: Infant risk cannot be ruled out.