Aspirin

Generic Name: Acetylsalicylic Acid (ASA)
Common Brand Names: Bayer Aspirin, Ecotrin, Bufferin, Disprin

Introduction

Aspirin is one of the most widely used medications globally, classified as a nonsteroidal anti-inflammatory drug (NSAID). It is known for its analgesic, antipyretic, and anti-inflammatory properties. Aspirin is also used in cardiovascular medicine for its antiplatelet effects.

Conditions of Use (Indications)

1. Pain and Fever: Used to relieve mild to moderate pain, including headaches, menstrual cramps, and muscle aches.
2. Inflammatory Disorders: Effective in conditions such as rheumatoid arthritis and osteoarthritis.
3. Cardiovascular Prevention: Used as a prophylaxis for myocardial infarction, ischemic stroke, and transient ischemic attacks (TIAs).
4. Acute Coronary Syndrome (ACS): Administered during acute heart attacks or unstable angina to reduce clot formation.
5. Kawasaki Disease (in children): Used under strict medical supervision to prevent coronary complications.

Mechanism of Action

Aspirin works primarily by irreversibly inhibiting the cyclooxygenase (COX) enzymes, COX-1 and COX-2, which are responsible for prostaglandin and thromboxane synthesis.

1. Pain and Inflammation: By blocking COX-2, aspirin decreases the production of prostaglandins, which mediate pain, fever, and inflammation.
2. Antipyretic Effect: Acts on the hypothalamus to promote vasodilation and sweating, reducing fever.
3. Antiplatelet Effect: Aspirin irreversibly acetylates COX-1 in platelets, inhibiting thromboxane A2 production. This reduces platelet aggregation and clot formation for the lifespan of the platelet (~7 days)

Side Effects

1. Common:

• Nausea, vomiting, and dyspepsia
• Heartburn and mild abdominal pain

1. Serious:

• Gastrointestinal bleeding or ulceration
• Tinnitus (ringing in the ears), particularly at higher doses
• Reye’s Syndrome in children (if used during viral infections)
• Hypersensitivity reactions (e.g., asthma exacerbation)
• Hemorrhagic stroke (rare but possible in high doses)

Harmful Interactions

1. Anticoagulants (e.g., warfarin, heparin): Increased risk of bleeding.
2. Corticosteroids: Increased risk of gastrointestinal ulcers and bleeding.
3. NSAIDs: Additive gastrointestinal toxicity when combined.
4. Selective Serotonin Reuptake Inhibitors (SSRIs): Increased risk of upper GI bleeding.
5. Alcohol: Increased risk of gastric mucosal damage and bleeding.

Contraindications

1. Active peptic ulcer disease or history of severe gastrointestinal bleeding
2. Aspirin allergy or hypersensitivity to NSAIDs
3. Children and teenagers with viral illnesses (due to the risk of Reye’s Syndrome)
4. Hemophilia or other bleeding disorders
5. Severe renal or hepatic impairment
6. Third trimester of pregnancy (risk of premature closure of the ductus arteriosus)

Latest References

1. FitzGerald, G. A. (2022). “The Evolving Role of Aspirin in Cardiovascular Disease.” The New England Journal of Medicine. DOI: 10.1056/NEJMoa1907976
2. Patrono, C. et al. (2021). “Aspirin Therapy in Cardiovascular Disease Prevention.” Circulation Research. DOI: 10.1161/CIRCRESAHA.120.318054
3. FDA. (2023). “Labeling for Aspirin: Uses, Dosage, and Safety.” U.S. Food and Drug Administration.