Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and inflammation, and as an antithrombotic. It is one of the oldest medications, with a history spanning hundreds of years. A precursor to aspirin, found in the bark of the willow tree (genus Salix), has been used for its medicinal properties for at least 2,400 years. By 1899, the German company Bayer named the compound “Aspirin” and began selling it globally.
What is the Dose of Aspirin?
The appropriate dose depends on the intended use:
- Pain relief: 300mg tablets, up to 4 times per day
- Reducing fever: 300-900mg
- Vascular disease:
Prevention of heart attack and stroke: 75-300mg (81mg in the USA)
After a heart attack or stroke: Initial 300mg, followed by 75mg per day
To prevent further heart attacks and strokes: 75mg per day
After a stent: 300mg initially, then 75mg per day
After coronary bypass surgery: 75mg per day
How Does Asprin Work?
Aspirin acts as a platelet inhibitor. Platelets are key components in blood coagulation and play a significant role in clot formation during heart attacks. By inhibiting this process, aspirin has proven beneficial in numerous clinical situations, particularly for patients who have experienced a myocardial infarction (heart attack), unstable angina, or chronic stable angina.
When Should Aspirin NOT be Used?
Aspirin should not be used in the following situations:
- Active peptic ulceration
- Bleeding disorders
- Children under 16 years (due to the risk of Reye’s syndrome)
- Haemophilia
- Previous peptic ulceration (at analgesic doses)
- Severe cardiac failure (at analgesic doses)
- During breastfeeding
- Severe renal or liver impairment (should be avoided or used with caution)
Frequently Asked Questions
Can I Use Aspirin for Atrial Fibrillation?
The benefit of aspirin in atrial fibrillation is less significant compared to Warfarin. It is currently not recommended for this condition.
What are the Disadvantages of Aspirin?
Some patients cannot tolerate aspirin due to gastric irritation, which can lead to gastritis, ulcers, or bleeding of the stomach lining.
It can also cause asthmatic attacks or bronchospasms in some individuals.
As a blood thinner, aspirin can increase the risk of bleeding in the brain, gut, and skin.
High doses may cause hearing problems and fluid retention.
Can Aspirin Use Prevent Cancer?
Aspirin may reduce the overall risk of developing and dying from certain cancers, particularly colorectal cancer (CRC). However, it must be taken for at least 10–20 years to observe this benefit. There is also some evidence suggesting it may slightly reduce the risk of endometrial and prostate cancers, though the evidence is not strong enough to recommend it solely for cancer prevention at this time.
Can You be Resistant to Aspirin?
Routine testing for aspirin resistance is not typically done. However, if cardiovascular events occur despite taking aspirin, resistance can be tested for.
