Overview
Acetylsalicylic Acid (Aspirin) is a nonsteroidal anti-inflammatory drug (NSAID) with analgesic, antipyretic, anti-inflammatory, and antiplatelet properties. It is widely used for pain relief, fever reduction, inflammation management, and cardiovascular protection through platelet inhibition.
Mechanism of Action
Irreversibly inhibits cyclooxygenase (COX-1 and COX-2) enzymes, reducing prostaglandin and thromboxane synthesis. This provides analgesic, antipyretic, and anti-inflammatory effects. Antiplatelet action occurs through inhibition of thromboxane A2 in platelets.
Indications
- Mild to moderate pain
- Fever
- Inflammatory conditions (e.g., rheumatoid arthritis)
- Acute coronary syndromes
- Secondary prevention of myocardial infarction and stroke
- Kawasaki disease
Dosage
Adults: Pain/fever: 325-650 mg every 4-6 hours (max 4 g/day). Antiplatelet: 75-325 mg daily. Children: Consult pediatric dosing (avoid in viral illnesses due to Reye's syndrome risk).
Contraindications
- Hypersensitivity to salicylates or NSAIDs
- Active peptic ulcer disease
- Hemophilia or bleeding disorders
- Severe hepatic or renal impairment
- Third trimester of pregnancy
- Children with viral infections (Reye's syndrome risk)
Side Effects
- Gastrointestinal: nausea, dyspepsia, ulceration, bleeding
- Hematologic: increased bleeding time
- Allergic: rash, anaphylaxis
- Renal: impaired function
- Tinnitus at high doses
- Reye's syndrome (in children)
Interactions
- Anticoagulants (warfarin): increased bleeding risk
- Other NSAIDs: increased GI toxicity
- Methotrexate: increased toxicity
- ACE inhibitors/ARBs: reduced antihypertensive effect
- Corticosteroids: increased ulcer risk
- Alcohol: increased GI bleeding risk