Aspirin

Aspirin, also known as acetylsalicylic acid (ASA), is a salicylate medication, often used to treat pain, fever, and inflammation.

Aspirin also has an antiplatelet effect by stopping the binding together of platelets and preventing a patch over damaged walls of blood vessels. 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. 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.  Aspirin may be effective at preventing certain types of cancer, particularly colorectal cancer.

The main side effects of aspirin are gastric ulcers, stomach bleeding, and ringing in the ears, especially with higher doses. While daily aspirin can help prevent a clot-related stroke, it may increase risk of a bleeding stroke (hemorrhagic stroke). In children and adolescents, aspirin is not recommended for flu-like symptoms or 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 most other NSAIDs in the mechanism of action. The salicylates have similar effects (antipyretic, anti-inflammatory, analgesic) to the other NSAIDs and inhibit the same enzyme cyclooxygenase (COX), but aspirin does so in an irreversible manner and, unlike others, affects the COX-1 variant more than the COX-2 variant of the enzyme.

The therapeutic properties of willow tree bark have been known for at least 2,400 years, with Hippocrates prescribing it for headaches.^[12] Salicylic acid, the active ingredient of aspirin, was first isolated from the bark of the willow tree in 1763 by Edward Stone of Wadham College, University of Oxford. Felix Hoffmann, a chemist atBayer, is credited with the synthesis of aspirin in 1897, though whether this was of his own initiative or under the direction of Arthur Eichengrün is controversial. 

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). It is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system.

Medical use

Aspirin is used in the treatment of a number of conditions, including fever, pain, rheumatic fever, and inflammatory diseases, such as rheumatoid arthritis, pericarditis, andKawasaki disease. Lower doses of aspirin have also shown to reduce the risk of death from a heart attack, or the risk of stroke in some circumstances. There is some evidence that aspirin is effective at preventing colorectal cancer, though the mechanisms of this effect are unclear.

Pain

Aspirin is an effective analgesic for acute pain, but is generally considered inferior to ibuprofen for the alleviation of pain because aspirin is more likely to causegastrointestinal bleeding. Aspirin is generally ineffective for those pains caused by muscle cramps, bloating, gastric distension, or acute skin irritation. As with other NSAIDs, combinations of aspirin and caffeine provide slightly greater pain relief than aspirin alone. Effervescent formulations of aspirin, such as Alka-Seltzer or Blowfish, relieve pain faster than aspirin in tablets, which makes them useful for the treatment of migraines. Topical aspirin may be effective for treating some types of neuropathic pain.

Headache

Aspirin, either by itself or in a combined formulation, effectively treats some types of headache, but its efficacy may be questionable for others. Secondary headaches, meaning those caused by another disorder or trauma, should be promptly treated by a medical provider.

Among primary headaches, the International Classification of Headache Disorders distinguishes between tension headache (the most common), migraine, and cluster headache. Aspirin or other over-the-counter analgesics are widely recognized as effective for the treatment of tension headache.

Aspirin, especially as a component of an acetaminophen/aspirin/caffeine, is considered a first-line therapy in the treatment of migraine, and comparable to lower doses ofsumatriptan. It is most effective at stopping migraines when they are first beginning.

Fever

Like its ability to control pain, aspirin’s ability to control fever is due to its action on the prostaglandin system through its irreversible inhibition of COX. Although aspirin’s use as an antipyretic in adults is well-established, many medical societies and regulatory agencies (including the American Academy of Family Physicians, the American Academy of Pediatrics, and the U.S. Food and Drug Administration (FDA)) strongly advise against using aspirin for treatment of fever in children because of the risk ofReye’s syndrome, a rare but often fatal illness associated with the use of aspirin or other salicylates in children during episodes of viral or bacterial infection.Because of the risk of Reye’s syndrome in children, in 1986, the FDA required labeling on all aspirin-containing medications advising against its use in children and teenagers.

Inflammation

Aspirin is used as an anti-inflammatory agent for both acute and long-term inflammation, as well as for treatment of inflammatory diseases, such as rheumatoid arthritis.

Heart attacks and strokes

Aspirin is an important part of the treatment of those who have had a myocardial infarction (heart attack). One trial found that among those likely having a ST-segment elevation MI, aspirin saves the life of 1 in 42 by reducing the 30-day death rate from 11.8% to 9.4%. There was no difference in major bleeding, but there was a small increase in minor bleeding amounting to roughly 1 in every 167 people given aspirin.