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Acetylsalicylic acidAka: Aspirin, ASA

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  1. Indications
    1. Prevention of coronary and cerebrovascular events
    2. Analgesia in rheumatic conditions
  2. Contraindications
    1. Children with viral illness (Varicella, Influenza)
      1. Risk of Reye's Syndrome
    2. Gout
    3. Hypersensitivity to Aspirin
    4. Active Peptic Ulcer Disease
  3. History
    1. Willow bark contains Salicin (Salicylic acid)
      1. Used in folk medicine for mild pain and fever
    2. Acetylsalicylic acid is a derivative of salicylic acid
      1. Synthesized in 1853 by the Bayer brothers
  4. Mechanism
    1. Antiinflammatory effect
      1. Inhibits prostaglandin biosynthesis
    2. Analgesic effect
      1. Relieves pain of mild to moderate intensity
    3. Antipyretic (Lowers temperature)
    4. Platelet Effects
      1. Inhibits Thromboxane synthesis
      2. Inhibits platelet aggregation
      3. Effects last 8 days (until new platelets)
  5. Dosing
    1. Use lowest appropriate dose (reduces adverse effects)
    2. Anticoagulation (Anti-Platelet action)
      1. General
        1. Do not exceed 160 mg qd if on Coumadin
      2. Acute Myocardial Infarction
        1. Primary prevention: 81 mg PO qd
        2. Immediate Myocardial Infarction Management: 325 mg
        3. Tertiary prevention (post-MI): 325 mg PO qd
      3. Cerebrovascular Accident
        1. Prevention in known vascular disease: 160-325 mg qd
        2. O'Connor (2001) Am J Cardiol 88:541
    3. Antipyretic or Analgesic Dose
      1. Adult: 600 mg PO q4 hours
      2. Adult: 650-1000 mg PO q4-6 hours
    4. Antiinflammatory dose
      1. Adult: 4 grams maximum per day
  6. Drug Interactions
    1. Ibuprofen inactivates Aspirin Anticoagulation effect
      1. Competes for same receptors
      2. Naprosyn and Indocin do not do this
  7. Effects
    1. Analgesic effect for mild to moderate pain at low dose
    2. Antiinflammatory effect at high dose
    3. Antipyretic effect
    4. Inhibition of platelet aggregation
      1. Irreversible platelet inhibition after single dose
      2. Effect lasts for the lifetime of platelet (8-10 days)
  8. Pharmacokinetics
    1. Duration: 4 hours
  9. Advantages
    1. Safer and lower cost than many NSAIDs
    2. Aspirin is an underused medication
  10. Adverse effects
    1. Gastrointestinal Effects
      1. Gastrointestinal intolerance
      2. Peptic Ulcer Disease (Erosive Gastritis)
        1. Aspirin higher risk for Peptic Ulcer Disease
        2. Other Salicylates have lower risk than most NSAIDs
      3. Gastrointestinal Bleeding
        1. Middle aged: 2-4 per 1000 on aspirin 5 years
        2. Older patient: 4-12 per 1000 on aspirin for 5 years
        3. Roderick (1993) Br J Clin Pharmacol 35:219
    2. Central Nervous System Effects: Salicylism
      1. Tinnitus
      2. Decreased hearing acuity
      3. Vertigo
    3. Central Respiratory effects
      1. Very high dose: Hyperpnea
      2. Lethal doses: Respiratory depression or apnea
    4. Miscellaneous Effects
      1. Serum Uric Acid changes
        1. Aspirin <2 g/day: increases serum Uric Acid
        2. Aspirin >4 g/day: lowers serum Uric Acid <2.5 mg/dl
      2. Asymptomatic hepatitis
      3. Exacerbation of renal insufficiency
      4. Hypersensitivity Reaction (Aspirin Allergy)
        1. Associated with Nasal Polyps and Asthma
  11. Dose related effect
    1. Therapeutic Levels
      1. Plasma Salicylate level <10 mg/dl: Analgesic effect
      2. Plasma Salicylate level <50 mg/dl: anti-inflammatory
    2. Overdosage levels
      1. Plasma Salicylate level <80 mg/dl: mild toxicity
        1. Tinnitus
        2. Hyperventilation
      2. Plasma Salicylate level <110 mg/dl: Moderate toxicity
        1. Fever
        2. Metabolic Acidosis
      3. Plasma Salicylate level <110 mg/dl: Severe toxicity
        1. Coma
        2. Cardiovascular instability
      4. Plasma Salicylate level <110 mg/dl: Lethal toxicity
        1. Renal Failure
        2. Respiratory failure
  12. Overdosage management
    1. Serious toxicity occur with ingestion >150 mg/kg
    2. Gastric Lavage
    3. Load crystalloid to maintain urine output
    4. Alkalinizing urine increases aspirin excretion
  13. References
    1. McCarty (1972) Arthritis and Allied Conditions
    2. Katzung (1989) Basic and Clinical Pharmacology
    3. (2000) Med Lett Drugs Ther 42(1085):73

Aspirin (C0004057)

Definition (MSH)The prototypical analgesic used in the treatment of mild to moderate pain. It has anti-inflammatory and antipyretic properties and acts as an inhibitor of cyclooxygenase which results in the inhibition of the biosynthesis of prostaglandins. Aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. (From Martindale, The Extra Pharmacopoeia, 30th ed, p5)
Definition (CSP)prototypical analgesic used in the treatment of mild to moderate pain; has antiinflammatory and antipyretic properties and acts as an inhibitor of cyclooxygenase which results in the inhibition of the biosynthesis of prostaglandins; aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis.
Definition (NCI)A drug that reduces pain, fever, inflammation, and blood clotting. Aspirin belongs to the family of drugs called nonsteroidal anti-inflammatory agents. It is also being studied in cancer prevention.
Definition (PDQ)An orally administered non-steroidal antiinflammatory agent. Acetylsalicylic acid binds to and acetylates serine residues in cyclooxygenases, resulting in decreased synthesis of prostaglandin, platelet aggregation, and inflammation. This agent exhibits analgesic, antipyretic, and anticoagulant properties. Check for "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=39152&idtype=1" active clinical trials or "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=39152&idtype=1&closed=1" closed clinical trials using this agent. ("http://nciterms.nci.nih.gov:80/NCIBrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&code=C287" NCI Thesaurus)
Definition (NCI)An orally administered non-steroidal antiinflammatory agent. Acetylsalicylic acid binds to and acetylates serine residues in cyclooxygenases, resulting in decreased synthesis of prostaglandin, platelet aggregation, and inflammation. It exhibits analgesic, antipyretic, and anticoagulant properties. (NCI04)
ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121)
Englishacetylsalicyclic acid, Acetylsalicylic Acid, Antiplatelet aspirin, ASA, Aspirin, ASPIRIN PREPARATION, Aspirin product
Spanishácido acetilsalicílico, AAS, acido acetilsalicilico, aspirina, aspirina como antiplaquetario, aspirina como tratamiento antiplaquetario, producto con aspirina para tratamiento antiagregante
CreditsDerived from the NIH UMLS (Unified Medical Language System)



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