TheCardiovascular
Reference

🟠 Aspirin (Acetylsalicylic acid)

Contents (13)

Indications

  • Acute myocardial infarction.

  • Unstable coronary artery disease.

  • Stable angina pectoris.

  • Secondary prophylaxis to prevent recurrence of cerebrovascular diseases, such as:

  • Transient ischemic attacks (TIA).
    • Stroke

    • Contraindications

    • Cross-reactivity: Do not administer to patients with a history of asthma, rhinitis, or urticaria triggered by:
  • Acetylsalicylic acid (aspirin).
    • Other non-steroidal anti-inflammatory drugs (NSAIDs).
    • Other contraindications:
  • Hemophilia.

    • Thrombocytopenia.

    • Active gastric or duodenal ulcers.

    • Liver cirrhosis.

    • Severe heart failure.

    • Doses > 100 mg/day during the third trimester of pregnancy.

    • Dosage

    • Acute myocardial infarction:
  • Initial loading dose: 300–500 mg as soon as possible after symptom onset.
    • Prophylaxis against cardiovascular complications (after acute myocardial infarction, unstable coronary artery disease, or stable angina pectoris):
  • 75–80 mg tablet once daily.
    • Prophylaxis against recurrence of cerebrovascular disease:
  • 75–80 mg tablet once daily.

    • Warnings and precautions

    • Use Aspirin with caution in the following cases:
  • Concurrent anticoagulant therapy (e.g., coumarin derivatives or heparin—except low-dose heparin).

    • Patients with gastrointestinal disorders.

    • Patients with severe kidney disease (glomerular filtration rate < 30 mL/min).

    • Patients with mild to moderate heart failure, kidney or liver disease, especially when combined with diuretics (risk of fluid retention and impaired kidney function).

    • Patients with bronchial asthma, chronic obstructive pulmonary disease, hay fever, or nasal polyps (increased risk of hypersensitivity reactions, such as asthma attacks, angioedema, or urticaria with NSAIDs).

    • Alcohol consumption may increase the risk of gastrointestinal bleeding.

    • Serious skin reactions (e.g., Stevens-Johnson syndrome, toxic epidermal necrolysis, DRESS syndrome) have been rarely reported with acetylsalicylic acid. Discontinue acetylsalicylic acid at the first sign of skin rash, mucosal lesions, or hypersensitivity.

    Interactions

    Pharmacodynamic interactions

    • Anticoagulants, thrombolytics, or other platelet aggregation inhibitors:
  • Salicylates inhibit platelet function and enhance the effect of anticoagulants, increasing bleeding risk. Monitor coagulation.
    • Cyclosporine, tacrolimus:
  • NSAIDs may increase the nephrotoxic effects of cyclosporine and tacrolimus. Monitor kidney function.
    • Diuretics and antihypertensives:
  • NSAIDs may reduce the efficacy of diuretics and antihypertensives. Risk of acute kidney injury increases when combined with ACE inhibitors.
    • Corticosteroids and other NSAIDs:
  • Increased risk of gastrointestinal bleeding when combined with acetylsalicylic acid.
    • Uric acid excretion agents (e.g., probenecid):
  • Salicylates counteract the effect of probenecid. Avoid combination.
    • Ibuprofen:
  • May inhibit the antiplatelet effect of low-dose acetylsalicylic acid when taken simultaneously. Clinical significance is unclear.
    • Metamizole:
  • May reduce the antiplatelet effect of acetylsalicylic acid. Use with caution in patients on low-dose acetylsalicylic acid for cardioprotection.

    • Pharmacokinetic interactions

    • Methotrexate:
  • NSAIDs inhibit tubular secretion of methotrexate, increasing plasma levels and risk of toxicity. Avoid combination with high-dose methotrexate.
    • Digoxin and lithium:
  • Acetylsalicylic acid inhibits renal excretion, increasing plasma levels. Monitor levels and adjust doses as needed.
    • Valproic acid:
  • Acetylsalicylic acid may reduce valproate binding to serum albumin, increasing free plasma levels.
    • Phenytoin:
  • Salicylates reduce phenytoin binding to plasma albumin, but the therapeutic effect remains unchanged.
    • Sulfonylureas:
  • Salicylates may potentiate the hypoglycemic effect of sulfonylureas, possibly due to reduced binding to serum albumin.
    • Nicotinic acid:
  • Acetylsalicylic acid may increase plasma levels of nicotinic acid, likely due to competitive inhibition of glycine conjugation.

    Pregnancy

    • Low doses (up to 100 mg/day):
  • Clinical studies suggest doses up to 100 mg/day appear safe but require monitoring.
    • Doses of 100–500 mg/day:
  • Insufficient clinical experience. Follow recommendations for higher doses.
    • Doses of 500 mg/day and higher:
  • Inhibition of prostaglandin synthesis may negatively affect pregnancy.
    • Risks include:
  • Increased risk of miscarriage.

    • Risk of heart defects and gastroschisis (especially in early pregnancy).

    • The absolute risk of cardiovascular malformation increases from <1% to ~1.5%.

    • Risk increases with higher doses and longer treatment duration.

    • Animal studies:
  • Increased pre- and post-implantation abortion, embryo/fetal death, and malformations (e.g., cardiovascular).
    • Recommendations:
  • Use only if absolutely necessary during the **first and second trimesters**.

    • Use the lowest effective dose for the shortest duration.

    • Contraindicated in the third trimester (doses >100 mg/day) due to risks of:

  • Cardiopulmonary toxicity (premature closure of ductus arteriosus, pulmonary hypertension).

    • Impaired fetal kidney function (risk of renal failure and reduced amniotic fluid).

    • Increased bleeding risk and inhibition of uterine contractions (delayed/prolonged labor).

    • Breastfeeding

    • Small amounts of salicylates and metabolites are excreted in breast milk.

    • Short-term use at therapeutic doses:

  • No need to interrupt breastfeeding (no reported side effects in infants).
    • Long-term use or high doses:
  • Discontinue breastfeeding.

    • Fertility

    • Acetylsalicylic acid may impair fertility in women.

    • Not recommended for women planning pregnancy.

    • Discontinuation should be considered in women with fertility issues or undergoing fertility evaluation.

    Driving and operating machinery

    • Acetylsalicylic acid has no known effects on the ability to drive or operate machinery.

    Side effects

    • Most common: Dyspepsia (2–6%).

    • Increased bleeding tendency (especially gastrointestinal) is rarely symptomatic.

    Frequency of Side Effects:

    • Common (>1/100):
  • Blood: Increased bleeding tendency.
    • GI: Dyspepsia.
    • Less common (>1/1000, <1/100):
  • General: Allergic reactions (urticaria, rhinitis, asthma).
    • Rare (<1/1000):
  • GI: Severe gastrointestinal bleeding.

    • CNS: Intracranial bleeding.

    • Skin: Stevens-Johnson syndrome, toxic epidermal necrolysis, DRESS syndrome.

    • Urogenital: Kidney dysfunction.

    • Special populations:
  • Individuals with allergies or asthma are at higher risk of hypersensitivity reactions.

    • Minor blood loss may lead to anemia in rare cases.

    • Severe gastrointestinal bleeding occurs only with higher doses and regular use.

    • Overdose symptoms:
  • Dizziness, tinnitus, hearing loss, agitation, hallucinations, tremors, hyperventilation, sweating, nausea, vomiting, abdominal pain.
    • Severe cases: Unconsciousness, seizures, hyperthermia, metabolic acidosis, respiratory alkalosis, hypoglycemia/hyperglycemia, hypokalemia, dehydration, oliguria, coagulopathy, liver damage, lung edema, rhabdomyolysis, kidney failure.

    • Overdose management

    • Symptomatic and supportive care.

    • Gastric lavage if indicated.

    • Activated charcoal (repeated doses).

    • Rehydration, correction of acidosis, and electrolyte imbalances.

    • Alkalinization of urine with sodium bicarbonate for accelerated elimination.

    • Monitor coagulation status; administer vitamin K, platelet concentrate, or fresh frozen plasma if needed.

    • Consider hemodialysis in severe cases (high salicylate levels, acidosis, CNS effects, or kidney failure).

    Pharmacodynamics

    • Mechanism of action: Inhibits platelet aggregation by irreversibly acetylating cyclooxygenase, preventing thromboxane A2 formation.

    • The effect lasts for the platelet's lifespan (7–10 days).

    • Renal effects: Inhibits renal prostacyclin synthesis, which may lead to acute kidney failure, fluid retention, and heart failure in patients with renal, cardiac, or liver insufficiency.

    Pharmacokinetics

    • Absorption:
  • Primarily in the small intestine and stomach.
    • Peak plasma concentration within 40 minutes.
    • Metabolism:
  • Hydrolyzed to salicylic acid (half-life: 30 minutes).
    • Salicylic acid is 80% protein-bound.
    • Elimination:
  • Dose-dependent; half-life is 2–4 hours for doses <3 g/day.
    • Excreted mainly via the kidneys.
    • Formulation:
  • Magnesium oxide is added to accelerate dissolution in the gastrointestinal tract.

    • Updated February 1, 2025

    ← All articles

    Relaterade artiklar

    Relaterade tester