Aspirin (USAN), also known as acetylsalicylic acid (pronounced /əˌsɛtɪlsælɪˌsɪlɪk ˈæsɪd/, abbreviated ASA), is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication.
Aspirin also has an antiplatelet effect by inhibiting thromboxane prostaglandins, which under normal circumstances bind platelet molecules together to repair damaged blood vessels. This is why aspirin is used in long-term, low doses to prevent heart attacks, strokes, and blood clot formation in people at high risk for developing blood clots. It has also been established that low doses of aspirin may be given immediately after a heart attack to reduce the risk of another heart attack or of the death of cardiac tissue.
The main undesirable side effects of aspirin are gastrointestinal ulcers, stomach bleeding, and tinnitus, especially in higher doses. In children and adolescents, aspirin is no longer used to control flu-like symptoms or the symptoms of chickenpox or other viral illnesses, due to the risk of Reye's syndrome.
Aspirin was the first discovered member of the class of drugs known as non-steroidal anti-inflammatory drugs (NSAIDs), not all of which are salicylates, although they all have similar effects and most have inhibition of the enzyme cyclooxygenase as their mechanism of action. Today, aspirin is one of the most widely used medications in the world, with an estimated 40,000 metric tons of it being consumed each year. In countries where Aspirin is a registered trademark owned by Bayer, the generic term is acetylsalicylic acid (ASA).