Aspirin

Aspirin is the commercial name of a drug developed by pharmaceutical company Bayer in the nineteenth century, using an extract of the bark of the willow tree. Its active ingredient is acetylsalicylic acid. There is evidence in the archaeological record showing that willow tree bark has been used for medicinal purposes as far back as 2000 BCE. Typically the drug is used to treat pain, inflammation, and swelling. In the latter half of the twentieth century, not long after its biochemical mechanisms were at last understood, researchers observed that aspirin also inhibits the clotting of blood. This knowledge led to additional research into whether or not aspirin should be used to prevent heart attacks by thinning the blood and reducing the frequency of arterial blockages. While the exact scope of its benefits in this regard is still subject to debate, there is general agreement that aspirin does help reduce the risk of heart attacks.

Brief History

Medical texts that date back to the ancient civilization of Sumer contain the oldest references to the beneficial effects of tea made from willow bark. The Egyptians were also aware of its beneficial properties, and the Greek and Roman civilizations were likewise familiar with it. During Europe’s Middle Ages, physicians and folk healers remained aware of willow bark’s uses. Finally, in the eighteenth century, scientific research was begun to determine the substance and the mechanism responsible for willow bark’s effects. Several researchers were able to isolate the active ingredient and identify it as salicin by the early nineteenth century, and Charles Frederic Gerhardt synthesized a more stomach friendly "buffered" compound, acetylsalicylic acid, in 1853.

In 1899, drug manufacturer Bayer began selling its product, named Aspirin, for the treatment of fever and for pain relief. The drug quickly grew in popularity around the world, helped in part by the Spanish flu epidemic after World War I, which provided a venue for the drug to showcase its potency. Aspirin generated huge profits for drug companies all over the world, most of them producing the drug independently, without the authorization of Bayer. The trademarked name Aspirin soon came into the lexicon as the generic "aspirin," which is commonly listed as an ingredient in non-Bayer products.

Aspirin’s popularity slowed in the 1950s and 1960s, when alternatives to aspirin—acetaminophen and ibuprofen, most notably—entered the marketplace. These alternative drugs appealed especially to the small portion of the population who experienced an allergic reaction or stomach irritation attributable to aspirin. In 1981, aspirin was also linked to Reye syndrome in children, a potentially fatal complication following viral infections such as the flu or chickenpox. Aspirin came back into vogue not long after, however, as researchers began to notice its ability to prevent blood clotting (the conglomeration of blood cells into large masses that can block the flow of blood to various parts of the body, potentially resulting in strokes, heart attacks, and other ailments). It is now common practice for doctors to prescribe one aspirin per day for their patients who may be at risk for strokes and/or heart disease, since aspirin is unlikely to cause negative side effects and has been shown to reduce the incidence of heart attacks.

Overview

Recognized worldwide as a "wonder drug" usable for a multitude of common ailments, aspirin is a household staple and can be found in almost every first aid kit and medicine cabinet. While it has been in use for millennia, only in the last hundred years has its operation been fully understood. At the outset, it was believed that aspirin produced its effects by interfering with the functions of the central nervous system, and that in this way it was able to reduce sensations of pain travelling from nerve endings through the central nervous system to the brain. This explanation was eventually found to be incorrect, however, through an experiment in which the vagus nerve of animal subjects were severed. Because the administration of aspirin in these circumstances still resulted in pain relief, this was seen as compelling evidence that the drug had a localized effect that was independent of communication with the central nervous system.

Ultimately, it was determined that aspirin operates by interfering with the body’s production of prostaglandins. Prostaglandins are a type of local hormone. The body produces prostaglandins to accomplish many different functions; thus, they are "local" in the sense that they might be used in one area to produce an inflammatory reaction to a particular substance, while in another area or a different context, prostaglandins might be produced by the body in order to transmit information about sensations of pain from an extremity to the brain. Other prostaglandins are created as part of the mechanism that causes blood cells to stick to one another, forming clots. The clotting of blood is what prevents a minor injury from resulting in death due to exsanguination. The blood cells near an injury clot together to "plug the hole" created by the wound, in effect producing a combination bandage and seal over the wound in order to promote healing.

Because aspirin interferes with the body’s means of producing prostaglandins, it can help reduce some of the effects prostaglandins are meant to create. For example, when a person has a backache, the body creates prostaglandins in order to communicate from the back muscles to the brain the sensation of pain. If the message about the pain cannot be transmitted, then the person will be unaware (or at least less aware) of the pain, thus experiencing relief. Similarly, if a person’s blood has a tendency to clot more than is needed, increasing the risk of heart attack or stroke, then aspirin may be able to counteract this tendency by preventing the creation of the prostaglandins that the body uses to trigger the blood cells into becoming more adhesive to one another.

Bibliography

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"Is Aspirin a Dangerous Drug?" Jama 312.23 (2014): 2577. MEDLINE with Full Text. Web. 1 June 2015.

Largent, Mark A. Keep Out of Reach of Children: Reye's Syndrome, Aspirin, and the Politics of Public Health. New York: Bellevue, 2015. Print.

Russell, Jesse, and Ronald Cohn. History of Aspirin. Edinburgh: Pubmix, 2013. Print.

Smith, Tom, et al. "The Aspirin Foundation Scientific Conference: The History, the Present State and the Future of Aspirin Prophylaxis." Ecancermedicalscience 8.(2014): 388. MEDLINE with Full Text. Web. 1 June 2015.

Souter, Keith. An Aspirin a Day: The Wonder Drug That Could Save Your Life. London: O'Mara, 2011. Kindle file.

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