Aspirin, or acetylsalicylic acid (ASA), is a common drug that is generally used as a pain reliever for minor aches and pains, to reduce fever, and also as an anti-inflammatory drug.
Aspirin has also become increasingly popular as a drug to prevent clot-forming; it is used long-term in low doses to prevent heart attacks and strokes in high-risk patients.
Nowadays, aspirin is often given to patients immediately after a heart attack to prevent recurrence or cardiac tissue death.
This article will explain what aspirin is and what it is used for; we will also cover precautions, side effects, and any risks.
Contents of this article:
Fast facts on aspirin
Here are some key points about aspirin. More detail and supporting information is in the main article.
- Aspirin is one of the most widely used medications in the world
- Aspirin is a derivative of salicylate, which can be found in such plants as willow trees and myrtle
- Aspirin was the first non-steroidal anti-inflammatory drug to be discovered
- Apollo Moon astronauts had Aspirin included in their self-medication kits
- Aspirin interacts with a number of other drugs, including warfarin and methotrexate
What is aspirin?
Aspirin is commonly used to relieve pain, inflammation, and fever and prevent clot formation.
Aspirin is a non-steroidal anti-inflammatory drug (NSAID). NSAIDs are medications with the following effects:
- Analgesic - pain relief without anesthesia or loss of consciousness
- Antipyretic - reduces a fever
- Anti-inflammatory - in higher doses
Non-steroidal simply means they are not steroids, which often have similar effects.
As analgesics, NSAIDs are generally non-narcotic (do not cause insensibility or stupor). Aspirin was the first NSAID to be discovered.
Aspirin in its present form has been around for over 100 years and is still one of the most widely used medications in the world. It is estimated that approximately 35,000 metric tons of aspirin is consumed annually. Aspirin is a trademark owned by German pharmaceutical company - Bayer; the generic term for aspirin is acetylsalicylic acid (ASA).
Therapeutic uses of aspirin
Aspirin is one of the most commonly used drugs for the treatment of mild to moderate pain, as well as migraines and fever. For the treatment of moderate to severe pain, it is frequently used along with other opioid analgesic and NSAIDs.
Below are some of the therapeutic uses of aspirin:
- Mild to moderate pain
- Moderate to severe pain combined with other medications
- Rheumatic fever (in higher doses)
- Rheumatic arthritis (in higher doses)
- Many other inflammatory joint conditions (in higher doses)
- To inhibit platelet aggregations (blood clot formations) to reduce risk of transient ischemic attacks and unstable angina (in lower doses)
- For the prevention of stroke (in lower doses)
- For the prevention of myocardial infarction in patients with cardiovascular disease
- In the treatment of pericarditis
- In the treatment of coronary artery disease
- In the treatment of myocardial infarction
Aspirin and children
Acetaminophen (paracetamol, Tylenol) and ibuprofen are generally used for children; not aspirin. Aspirin and salicylate NSAID usage in children raise the risk of developing Reye's Syndrome. In some countries, such as the United Kingdom, aspirin is only occasionally used in children under specialist supervision for Kawasaki disease and to prevent blood clot formation after heart surgery.
Low-dose aspirin (75 milligrams per day) is used as an antiplatelet medication - to prevent the formation of clots in the blood.
Low-dose aspirin may be given to patients who had:
- A coronary artery bypass graft operation
- A heart attack
- A stroke
- Atrial fibrillation
- Acute coronary syndrome
The following people may also be given low-dose aspirin if the doctor believes they are at risk of heart attack or stroke:
- Patients with high blood cholesterol levels
- Patients with hypertension (high blood pressure)
- Patients with diabetes
- Some smokers
The following patients may also be advised to take low-dose aspirin:
- Those with damage to the retina (retinopathy)
- Some patients who have had diabetes for over 10 years
- Some patients who are taking antihypertensive medications
In all these cases, low-dose aspirin will be taken daily for the rest of the patient's life.
Precautions for aspirin use
Aspirin is not recommended for the following patients:
- People who have a peptic ulcer
- Patients with hemophilia or any other bleeding disorder
- People with a known allergy to aspirin
- People who are allergic to any NSAIDs, such as ibuprofen
- Children under 16 years of age (unless under specialist medical supervision)
The following people should be cautious about taking aspirin, and should only do so if the doctor agrees:
- Patients with asthma
- Patients with uncontrolled hypertension
- People who have had a previous peptic ulcer
- Patients with liver problems
- Patients with kidney problems
Anyone planning to have a surgical operation should tell their doctor if they are taking regular aspirin. In many cases, patients will be asked to stop taking the aspirin for 7 days before the operation.
Pregnant or breast-feeding patients may take low-dose aspirin, but only under their doctor's supervision. High-dose aspirin is not recommended.
Drug interactions with aspirin
If taken alongside anti-inflammatory painkillers such as ibuprofen and diclofenac, aspirin can increase the risk of stomach bleeding.
Sometimes, one medication can undermine the efficacy of another medication - this is called a drug interaction. Below is a list of the most common drugs that aspirin interacts with (there are more):
- Anti-inflammatory painkillers - such as diclofenac, ibuprofen, indomethacin, and naproxen increase the risk of stomach bleeding if taken in combination with aspirin.
- Methotrexate - used in the treatment of cancer and some autoimmune diseases. Aspirin can make it harder for the body to eliminate methotrexate, resulting in high and potentially dangerous levels of methotrexate in the body.
- SSRI (selective serotonin reuptake inhibitors) antidepressants - drugs, such as citalopram, fluoxetine, paroxetine, venlafaxine, and sertraline, taken with aspirin can increase the risk of bleeding.
- Warfarin - this is an anticoagulant drug (a blood thinner); it stops the blood from clotting. Aspirin taken with warfarin can reduce the drug's anticoagulant effects, increasing the risk of bleeding. In some situations, however, a doctor may prescribe aspirin together with warfarin.
Aspirin side effects
The most common side effects of aspirin are:
- Irritation of the stomach or gut
The following side effects are possible, but less common:
An extremely rare side effect of low-dose aspirin is hemorrhagic stroke.