VitalsCentral

Aspirin

Bayer | Ecotrin | Bufferin

OTCAnalgesicsNSAIDs
Half-life: Aspirin about 15-20 minutes; salicylate 2-3 hours at low dosesPregnancy: Category C

Overview

Aspirin is a salicylate NSAID with analgesic, antipyretic, anti-inflammatory, and antiplatelet properties, widely used for pain, fever, and cardiovascular prevention.

Indications

  • Mild to moderate pain
  • Fever
  • Inflammatory conditions
  • Secondary prevention of cardiovascular events

Contraindications

  • Active peptic ulcer or GI bleeding
  • Aspirin or NSAID hypersensitivity
  • Children with viral illness (Reye syndrome risk)
  • Severe bleeding disorders

Classification

AnalgesicsNSAIDsCardiovascular SystemMusculoskeletal System

Mechanism of Action

Irreversibly acetylates and inhibits cyclooxygenase enzymes (COX-1 and COX-2), reducing synthesis of prostaglandins and thromboxane A2. Low-dose inhibition of platelet thromboxane produces the antiplatelet effect.

Pharmacodynamics

At low doses provides antiplatelet activity; at higher doses provides analgesic, antipyretic, and anti-inflammatory effects. Platelet inhibition lasts for the life of the platelet.

Pharmacokinetics

Absorption
Rapidly absorbed from the stomach and upper small intestine.
Distribution
Salicylate is widely distributed and protein bound; distribution increases as protein binding saturates.
Metabolism
Rapidly hydrolyzed to salicylic acid, then conjugated in the liver.
Excretion
Excreted renally as salicylate and metabolites; elimination is pH dependent.
Half-life
Aspirin about 15-20 minutes; salicylate 2-3 hours at low doses
Bioavailability
50-75%
Protein Binding
Approximately 90% (salicylate, concentration dependent)

Dosage

Typical dosage: 81 mg daily for cardioprotection; 325-650 mg every 4-6 hours for pain

Available Forms

  • Tablet
  • Chewable tablet
  • Enteric-coated tablet
  • Suppository

Side Effects

Common

  • Dyspepsia
  • Nausea
  • Bruising
  • Prolonged bleeding time

Serious

  • Gastrointestinal bleeding
  • Peptic ulceration
  • Bronchospasm in sensitive individuals

Rare

  • Reye syndrome
  • Salicylate toxicity

Drug Interactions

Warfarinmajor

Additive bleeding risk from combined antiplatelet and anticoagulant effects.

Ibuprofenmoderate

Ibuprofen can competitively block the antiplatelet effect of low-dose aspirin.

Warnings

Pregnancy

Category C

Toxicity

Salicylate overdose causes tinnitus, hyperventilation, mixed acid-base disturbance, and, in severe cases, seizures and coma.

Overdose

Manage with activated charcoal, urinary alkalinization to enhance excretion, correction of fluid and electrolytes, and hemodialysis in severe poisoning.

References

Looking for patient-friendly information? Visit RemedyDoor for easy-to-read guides about this medication.