Aspirin

Skeletal formula of aspirin

Aspirin, also known as acetylsalicylic acid (ASA), is a medication used to reduce pain, fever, or inflammation. Specific inflammatory conditions which aspirin is used to treat include Kawasaki disease, pericarditis, and rheumatic fever. Aspirin is also used long-term to help prevent further heart attacks, ischemic stroke, and blood clots in people at high risk.

History

Aspirin advertisement from 1923

The use of aspirin dates back to ancient times when extracts of willow bark were used for pain relief. The active ingredient, salicin, was identified in the 19th century, and acetylsalicylic acid was synthesized by Felix Hoffmann at Bayer in 1897.

Chemical Structure

3D ball model of aspirin

Aspirin is a salicylate drug, and its chemical formula is C₉H₈O₄. It is an ester of salicylic acid and acetic anhydride.

Mechanism of Action

Aspirin works by inhibiting the enzyme cyclooxygenase (COX), which results in a decreased formation of prostaglandins and thromboxanes. This inhibition is irreversible, which is why aspirin has a prolonged effect on platelet function.

Synthesis

Synthesis of aspirin

Aspirin is synthesized through the acetylation of salicylic acid with acetic anhydride. The reaction is catalyzed by an acid, such as sulfuric acid or phosphoric acid.

Reaction Mechanism

Mechanism of acetylation of salicylic acid

The acetylation of salicylic acid involves the transfer of an acetyl group from acetic anhydride to the hydroxyl group of salicylic acid, forming aspirin and acetic acid as a byproduct.

Medical Uses

Aspirin is used for its analgesic, antipyretic, and anti-inflammatory properties. It is also used in low doses to reduce the risk of heart attack and stroke.

Side Effects

Common side effects include gastrointestinal bleeding, ulceration, and tinnitus. Aspirin should be used with caution in people with asthma or peptic ulcer disease.

Commercial Availability

Old package of aspirin

Bayer aspirin and generic aspirin on a store shelf

Aspirin is available over-the-counter in many countries and is sold under various brand names, including Bayer Aspirin.

Related Pages

• Nonsteroidal anti-inflammatory drug
• Salicylic acid
• Cyclooxygenase
• Thromboxane