asprin

Aspirin (USAN), also known as acetylsalicylic acid  abbreviated ASA), is a salicylate drug, often used as ananalgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. It was first isolated by Felix Hoffmann, a chemist with the German company Bayer, under the direction of Arthur Eichengrün.

Salicylic acid, the main metabolite of aspirin, is an integral part of human and animal metabolism. While much of it is attributable to diet, a substantial part is synthesized endogenously.

Aspirin also has an antiplatelet effect by inhibiting the production of thromboxane, which under normal circumstances binds platelet molecules together to create a patch over damaged walls of blood vessels. Because the platelet patch can become too large and also block blood flow, locally and downstream, aspirin is also used long-term, at low doses, to help prevent heart attacks, strokes, and blood clot formation in people at high risk of 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. Many people take a daily aspirin to reduce their risk of heart attack. Now fresh evidence suggests that the over-the-counter pain reliever may be a powerful tool in cancer prevention as well.

The main undesirable side-effects of aspirin taken by mouth are gastrointestinal ulcers, stomach bleeding, and tinnitus, especially in higher doses. In children and adolescents, aspirin is no longer indicated to control flu-like symptoms or the symptoms of chickenpox or other viral illnesses, because of the risk of Reye's syndrome.

Aspirin is part of a group of medications called nonsteroidal anti-inflammatory drugs (NSAIDs), but differs from them in the mechanism of action. Though it, and others in its group called the salicylates, have similar effects (antipyretic, anti-inflammatory, analgesic) to the other NSAIDs and inhibit the same enzyme cyclooxygenase, aspirin (but not the other salicylates) does so in an irreversible manner and, unlike others, affect more the COX-1 variant than the COX-2 variant of the enzyme.

Today, aspirin is one of the most widely used medications in the world, with an estimated 40,000 tonnes of it being consumed each year. In countries where Aspirin is a registered trademark owned by Bayer, the generic term is acetylsalicylic acid (ASA).

Medical uses

Aspirin is used for the treatment of a number of conditions including: fever, pain, rheumatic fever, and inflammatory diseases, such as rheumatoid arthritis,pericarditis, and Kawasaki disease. It is used in the prevention of transient ischemic attacks, strokes, heart attacks, pregnancy loss, and cancer.

Overdose

Main article: Aspirin poisoning

Aspirin overdose can be acute or chronic. In acute poisoning, a single large dose is taken; in chronic poisoning, higher than normal doses are taken over a period of time. Acute overdose has a mortality rate of 2%. Chronic overdose is more commonly lethal, with a mortality rate of 25%; chronic overdose may be especially severe in children. Toxicity is managed with a number of potential treatments, including activated charcoal, intravenous dextrose and normal saline, sodium bicarbonate, and dialysis. The diagnosis of poisoning usually involves measurement of plasma salicylate, the active metabolite of aspirin, by automated spectrophotometric methods. Plasma salicylate levels in general range from 30–100 mg/L after usual therapeutic doses, 50–300 mg/L in patients taking high doses and 700–1400 mg/L following acute overdose. Salicylate is also produced as a result of exposure to bismuth subsalicylate, methyl salicylate and sodium salicylate.

PARACETAMOL

Paracetamol INN ( /ˌpærəˈsiːtəmɒl/ or /ˌpærəˈsɛtəmɒl/), or acetaminophen USAN ⁱ/əˌsiːtəˈmɪnəfɨn/, is a widely used over-the-counter analgesic (pain reliever) and antipyretic (fever reducer). It is commonly used for the relief of headaches and other minor aches and pains and is a major ingredient in numerous cold and flu remedies. In combination with opioid analgesics, paracetamol can also be used in the management of more severe pain such as post-surgical pain and providing palliative care in advanced cancer patients.^[4] The onset of analgesia is approximately 11 minutes after oral administration of paracetamol,^[5] and its half-life is 1–4 hours. Though acetaminophen is used to treat inflammatory pain, it is not generally classified as an NSAID because it exhibits only weak anti-inflammatory activity.

While generally safe for use at recommended doses (1,000 mg per single dose and up to 4,000 mg per day for adults),^[6] acute overdoses of paracetamol can cause potentially fatal liver damage and, in rare individuals, a normal dose can do the same; the risk is heightened by alcohol consumption.Paracetamol toxicity is the foremost cause of acute liver failure in the Western world, and accounts for most drug overdoses in the United States, the United Kingdom, Australia and New Zealand.

It is the active metabolite of phenacetin, once popular as an analgesic and antipyretic in its own right, but unlike phenacetin and its combinations, paracetamol is not considered carcinogenic at therapeutic doses.^[11] The words acetaminophen (used in the United States, Canada, Japan, South Korea, Hong Kong, and Iran^[12]) and paracetamol (used elsewhere) both come from a chemical name for the compound: para-acetylaminophenol andpara-acetylaminophenol. In some contexts, it is simply abbreviated as APAP, for acetyl-para-aminophenol.