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Anaesthesia => Analgesic => Aspirin
Aspirin
Aspirin, synthetic chemical compound, acetylsalicylic acid, one of the analgesic class of painkilling drugs. It is made from salicylic acid, found in the bark of the willow tree, which was used by the ancient Greeks and Native Americans, among others, to counter fever and pain. Salicylic acid is bitter, however, and can irritate the stomach. The German chemist Felix Hoffman synthesized the acetyl derivative of salicylic acid in the 1890s in response to the urging of his father, who took salicylic acid for rheumatism.
Aspirin is currently the first-choice drug for fever, mild-to-moderate pain, and inflammation due to arthritis or injury. It acts at the site of tissue damage rather than in the pain centres of the brain, as do opiates such as codeine. It is a more effective analgesic than codeine. Aspirin causes insignificant gastrointestinal bleeding that can over time, however, cause iron deficiency; gastric ulcers may also occur with long-term use. Complications can be avoided by using enteric-coated aspirin, which does not dissolve until reaching the intestine. Aspirin should not be given to children because it increases the risk of contracting the rare and frequently fatal Reye's syndrome, a disease of the brain and some abdominal organs. An alternative anti-inflammatory analgesic, ibuprofen, does not carry this risk.
It has been found that aspirin acts by interfering with synthesis of prostaglandins, which are implicated in inflammation and fever. It does this by blocking the enzyme cyclo-oxygenase, which stimulates prostaglandin release. Studies of aspirin's effects on blood platelet aggregation, making the blood less liable to clotting, suggest that half an aspirin tablet per day may reduce the risk of heart attack and stroke in some individuals. A large study conducted in Britain and published at the end of 1993 indicated that long-term aspirin therapy can help prevent potentially fatal clots forming in blood vessels following bypass surgery and other operations. Evidence from research establishments in the United States and Britain suggests that a regular use of aspirin may also reduce the risk both of colon and rectal cancer and slow the formation of cataracts, and, additionally, that it may prevent migraine.
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