The Wonder of Aspirin

History

Acetylsalicylic acid was first synthesized in 1853 by von Gerhardt by mixing acetic acid with salicylic acid. It was first invented for arthritis. This medicine became the first pain reliever in tablet form. The name of aspirin means pain relief, speed, reliability, and tolerability. Aspirin was submitted to the Imperial Patent Office in Berlin, West Germany, in 1899.
In 1900, the medicine was also patented in the USA. The basic mechanism of aspirin's pain reliever relies on its antipyretic property. In only about 10-15 years, this medicine became "best seller" in the USA. Later in 1950, aspirin was included in the Guinness World Records for being the best-selling painkiller.

Broad Indications
Until today, more than a century after its invention, aspirin is still considered as one of top medicine ever invented. It has very broad indications besides painkiller and antipyretic: antimigraine, antiplatelet aggregation, rheumatoid arthritis, stroke/cerebrovascular accident, heart attack, pregnancy loss (antiphospholipid syndrome), several autoimmune diseases, and cancer.

Antipyretic
Even though possessing antipyretic effect, aspirin's antipyretic property has been overtaken by paracetamol. So that is the reason why almost all physicians prefer paracetamol to relieve fever rather than aspirin. Pernerstorfer et al in their study in 1999 showed that in febrile model in men; paracetamol elicited superior antipyretic effect than aspirin; when both medicines were given in the same doses. Paracetamol ameliorated subjective symptoms of endotoxemia without compromising the humoral response to a subject to endotoxin.

Painkiller
As a painkiller, Aspirin is used in dose of 500-1000 mg for each administration. For headache, Asian people usually needs only 325-500 mg. But in Europe or USA, the dosage may be higher (500-1000 mg). The more severe the pain, the higher the dose. In postsurgical setting, aspirin has moderate painkiller effect only when compared to opioid analgesic, so the medicine is not widely used for that purpose.
In Europe, it is regular that an adult needs 1000 mg dose to relieve headaches or migraine attack. The efficacy against migraine attack is comparable with triptans. Several European countries have formulated aspirin plus metoclopramide 10 mg, a dopamine agonist (gastrointestinal peristaltic regulator) for this indication.

Platelet Antiaggregation Agent
The dose of aspirin as platelet antiaggregation agent is about 80-325 mg. Asian people usually use dose of 80-160 mg, while Europeans/Americans use dose of 100-325 mg. This is the only platelet antiaggregation agent that can be used for lifetime, while clopidogrel is advised to be used for about 1 year only.
Aspirin works virtually by abolishing cyclooxygenase system in formation of prostacyclin (which is important for vasodilatation and platelet aggregation) and thromboxane A2 (which is important for platelet aggregation and vasoconstriction), thus making this medicine effective for antiplatelet function and treatment of pregnancy-induced hypertension.

Cancer Prevention
Aspirin taken for several years at doses of at least 75 mg daily reduced long-term incidence and mortality due to colorectal cancer, especially cancer on the proximal colon (Rothwell et al, 2010).

Adverse Effects
Besides its efficacy and broad indications, aspirin is well-known with its gastrointestinal irritative effect. That caused medicine formulation in enteric-coated tablet form. Also remember that this medicine also brings risk of gastrointestinal bleeding.


References
Aspirin® Official Website.
Pawar D et al. HKMJ 1998; 4(4): 415-418.
Pernerstorfer T et al. Clinical Pharmacology & Therapeutics 1999; 66: 51–57.
Rothwell PM et al. The Lancet 2010; 376: 1741-1750.