acetylsalicylic acid

B01AC06

Forms & Strengths

Adult Dosing

Secondary prevention of cardiovascular events: 81 mg to 325 mg orally once daily
Acute myocardial infarction / Acute ischemic stroke: 162 mg to 325 mg orally once (initial loading dose)
Analgesic / Antipyretic: 325 mg to 650 mg orally or rectally every 4 hours as needed (maximum 4 g/day)

Pediatric Dosing

Kawasaki disease (acute phase): 80 mg/kg/day to 100 mg/kg/day orally divided every 6 hours during febrile phase, then 3 mg/kg/day to 5 mg/kg/day once daily
Analgesic / Antipyretic: Not recommended due to risk of Reye syndrome
Routine use in pediatric patients for pain or fever is contraindicated

Indications

Reduction of mortality and nonfatal myocardial infarction in patients with a history of infarction or unstable angina pectoris
Chronic management and secondary prevention of ischemic stroke and transient ischemic attacks
Prophylaxis of myocardial infarction and stroke in patients with cardiovascular risk factors
Treatment of mild to moderate pain and fever
Management of Kawasaki disease

Mechanism of Action

Irreversibly inhibits cyclooxygenase (COX-1 and COX-2) enzymes via acetylation
Blocks synthesis of thromboxane A2 in platelets, preventing platelet aggregation for the lifespan of the platelet (7 to 10 days)
Exerts anti-inflammatory, analgesic, and antipyretic effects via inhibition of prostaglandin synthesis in the central and peripheral nervous systems

Contraindications

Hypersensitivity to salicylates or other nonsteroidal anti-inflammatory drugs (NSAIDs)
Patients with the triad of asthma, nasal polyps, and severe bronchospasm or anaphylaxis to aspirin or NSAIDs
Active pathological bleeding such as peptic ulcer disease or intracranial hemorrhage
Children and teenagers with viral infections (influenza or varicella) due to the risk of Reye syndrome
Severe hepatic impairment or bleeding disorders (e.g., hemophilia)

Adverse Reactions

Gastrointestinal ulceration, bleeding, perforation, dyspepsia, and nausea
Increased bleeding time, bruising, and hemorrhagic complications
Tinnitus, hearing loss, and dizziness (signs of salicylism at high doses)
Hypersensitivity reactions including bronchospasm, urticaria, angioedema, and anaphylaxis
Reye syndrome in pediatric populations with viral illness

Drug Interactions

Anticoagulants (e.g., warfarin, direct oral anticoagulants) and other antiplatelet agents significantly increase bleeding risk
Other NSAIDs (e.g., ibuprofen) may attenuate the cardioprotective antiplatelet effect of low-dose aspirin and increase gastrointestinal toxicity
ACE inhibitors, ARBs, and diuretics may have decreased efficacy and increased risk of renal impairment when co-administered with aspirin
Methotrexate clearance is reduced by salicylates, leading to severe bone marrow toxicity
Systemic corticosteroids may decrease salicylate concentrations and increase ulcerogenic risk

Curated Content: Needs Vetting Before Put to Clinical Use