The story of aspirin is as remarkable and wide ranging as the number of uses doctors are now finding for it. From origins as a herbal folk medicine - through its extended life as a front line pain killer – and now to its potential applications as a life saving preventive medicine, aspirin's role is constantly changing. All these developments have come from the efforts of thousands of doctors and scientists from across the world.
Major historical events:
c400 BC In Greece Hippocrates gives women willow leaf tea to relieve the pain of childbirth.
1763 Reverend Edward Stone of Chipping Norton near Oxford gives dried willow bark to 50 parishioners suffering rheumatic fever.
Describes his findings in a letter to the Royal Society of London.
1823 In Italy the active ingredient is extracted from willow and named salicin.
1838 Salicin also found in the meadowsweet flower by Swiss and German researchers.
1853 Salicylic acid made from salicin by French scientists but it is found to irritate the gut.
1893 German scientists find that adding an acetyl group to salicylic acid reduces its irritant properties.
1897 In Germany, Bayer's Felix Hoffmann develops and patents a process for synthesising acetyl salicylic acid or aspirin. First clinical trials begin.
1899 Clinical trials are successfully completed. aspirin launched.
1914 International trade in pharmaceuticals interrupted by the outbreak of World War I. Australian pharmacist G. R. Nicholas wins a competition to find a new way of producing aspirin.
1930s Bayer's patent on acetyl salicylic acid runs out. It becomes a generic drug.
1974 First evidence of aspirin's effects in preventing heart attacks: Professor Elwood.
1982 English scientist Professor Sir John Vane and two Swedish colleagues, Sune Bergström and Bengt Samuelsson win Nobel prize for discovering the role of aspirin in inhibiting prostaglandin production.
1989 US researchers report preliminary study suggesting that aspirin may delay the onset of senile dementia 1994 - Professor Henk C S Wallenburg of Rotterdam shows that aspirin may help in treating pre-eclampsia in pregnant women.
1995 American researchers find evidence that aspirin protects against bowel cancer.
1997 aspirin is now used or being tested for use in the following conditions:
aspirin is now accepted as an important weapon in the prevention of heart disease. After the first study by Elwood and Cochrane was reported in the British Medical Journal (1974, 1, 436) larger trials involving 20,000 US doctors showed that aspirin reduced the risk of coronary thrombosis by 44 per cent. A single dose of 300 mg is now recommended for patients in the acute stages of a heart attack followed by a daily dose of 75-100 mg. A similar low dose treatment regime is recommended for patients with angina, a history of heart problems or who have undergone coronary by pass surgery.
A trial reported in the Lancet this year (vol 349 p 1641) is the latest in a sequence of studies showing that aspirin reduces the risk of strokes in patients with 'early warning signs' of transient ischaemic attacks. Further trials showed a small but definite benefit in reducing mortality in those patients (T.I.A.’s) in the acute phase of a stroke.
Pre-eclampsia and foetal growth retardation, both caused by blockages of the blood vessels of the placenta, are two of the commonest complications of pregnancy - there are 50,000 cases of pre-eclampsia in Britain a year. In a trial involving more than 9000 women in 16 countries, a daily dose of 60 mg aspirin reduced the risk of pre-eclampsia by 13 per cent. Earlier research suggested that the benefits were even greater.
In a long term study of 90,000 US nurses between 1976 and 1995, those who took 4-6 tablets of aspirin a week had a reduced incidence of colorectal cancer. The benefits were greatest in those who had taken the drugs the longest.
Blindness, coronary artery disease, stroke and kidney failure are all common complications of diabetes resulting from impaired blood circulation. The benefits of taking one aspirin a day are now so widely accepted that it is considered unethical to perform placebo controlled trials to prove the case.
Dementia (including Alzheimer's disease)
Some form of dementia affects about one in four people aged 70 years or above. There is some evidence that aspirin may help prevent both the condition resulting from impaired blood flow and the most serious form of dementia, Alzheimer's disease. The latter is believed to be an inflammatory condition similar to arthritis. aspirin is a highly effective anti-inflammatory drug and a preliminary study found a lower than expected incidence in patients with rheumatoid arthritis, who frequently have to take aspirin over a prolonged period. An important trial in South Wales is following the fortunes of 400 men and studying the factors (including aspirin consumption) that may determine the incidence of dementia. However, volunteers are still being signed up for the trial and conclusive results will not be ready for some time.