Aspirin is one of the oldest medicines still in common use. It belongs to a class of medicines called salicylates, and works by suppressing the production of certain substances in the body that cause pain, fever and inflammation.
Aspirin also has an effect on platelets – cells in the blood that are involved in clotting. Taking aspirin reduces the ability of platelets to stick together and form clots, making it useful in the treatment and sometimes prevention of conditions where blood clots form in arteries, such as heart attack and stroke.
Aspirin for pain and fever
Aspirin can be used for the occasional treatment of mild to moderate pain and fever. It can be used for conditions such as headaches and migraines, period pain, toothache, cold and flu symptoms and joint and muscle pains.
Aspirin should not be given to children younger than 16 years who have a fever, especially if the child also has symptoms of influenza or chicken pox. This is because aspirin can cause a serious condition called Reye syndrome in children.
Aspirin for heart disease and stroke
A dose of aspirin is used by doctors as part of the initial emergency treatment for a heart attack.
Daily low-dose aspirin is recommended to prevent a second heart attack in those who have already had one. It may also be used to reduce the risk of heart attack in people with coronary artery disease, including angina. Daily low-dose aspirin can also be taken to prevent stroke and transient ischaemic attacks (TIAs, or mini-strokes) in people who have had a previous stroke or TIA.
Regular low dose aspirin therapy may also be recommended for certain people who have atrial fibrillation (a heart rhythm disorder) to prevent stroke – a known complication of atrial fibrillation.
Current Australian guidelines do not recommend the use of daily low-dose aspirin to prevent cardiovascular disease in people with no past history, including those thought to be at high risk.
You should always discuss with your doctor the risks and benefits of any medicines before taking them.
Side effects of aspirin
Regular use of aspirin increases your risk of developing a peptic ulcer in the stomach. Aspirin can also irritate the stomach, causing heartburn, nausea and vomiting.
Because aspirin ‘thins’ your blood, making it harder to clot, taking aspirin can increase your risk of bleeding, including bleeding from the gastrointestinal tract.
Aspirin can cause an allergic reaction in some people, resulting in skin rash, hives, wheezing and difficulty breathing.
Who should not take aspirin?
You should check with your doctor or pharmacist before taking aspirin, especially if you are taking any other regular medicines. Taking aspirin when you are already taking other medicines to prevent clotting, such as warfarin, can greatly increase your risk of bleeding.
The following people should avoid using aspirin.
- People who have experienced an allergic reaction to aspirin or non-steroidal anti-inflammatory medicines (NSAIDs).
- People with asthma who have a history of asthma symptoms being triggered by aspirin or other NSAIDs.
- Anyone with a recent history of a peptic ulcer (ulcer in the stomach or duodenum) or bleeding from the stomach or intestines.
- People with haemophilia and other bleeding disorders.
- Women who are pregnant or breast feeding.
- Children younger than 16 years of age who have a fever.
People taking regular aspirin may need to stop taking aspirin 7-10 days before having any surgery or dental work to reduce the risk of bleeding. Your doctor or surgeon will be able to advise you on this.
There are many different formulations of aspirin available, including:
- tablets (e.g. Aspro);
- chewable tablets (e.g. Disprin Direct); and
- dissolvable tablets (e.g. Dispirin, Solprin, Aspro Clear).
Low-dose aspirin comes as:
- tablets (e.g. Astrix tablets; Cardiprin 100); and
- enteric coated tablets or capsules, which have a special coating said to help protect the stomach from the effects of aspirin (e.g. Astrix 100, Cartia).
There is no evidence that the risk of gastrointestinal bleeding is different for plain, enteric coated or buffered aspirin.
You should take aspirin in the dose that is recommended for you and follow the instructions for use. Some types of aspirin should be taken with food to lessen stomach upset.
While aspirin is available over the counter, you shouldn’t take aspirin regularly without consulting your doctor.
If you are taking daily aspirin, it’s important that you don’t suddenly stop taking it as this could have a rebound effect and trigger a blood clot. Always talk to your doctor before stopping any regular medicines.
- 1. Aspirin (revised June 2011). In: eTG complete. Melbourne: Therapeutic Guidelines Limited; 2012 Nov. http://online.tg.org.au/complete/ (accessed Dec 2012).
2. Antiplatelet drugs (revised February 2012; amended October 2012). In: eTG complete. Melbourne: Therapeutic Guidelines Limited; 2012 Nov. http://online.tg.org.au/complete/ (accessed Dec 2012).
3. Cardiovascular disease risk stratification (revised October 2012). In: eTG complete. Melbourne: Therapeutic Guidelines Limited; 2012 Nov. http://online.tg.org.au/complete/ (accessed Dec 2012).
4. Drugs.com. Aspirin (reviewed 24 August 2009). http://www.drugs.com/aspirin.html (accessed Dec 2012).
5. Heart Foundation. Coronary heart disease. http://www.heartfoundation.org.au/information-for-professionals/Clinical-Information/Pages/coronary-heart-disease.aspx (accessed Dec 2012).
6. National Vascular Disease Prevention Alliance. Guidelines for the management of absolute cardiovascular disease risk; 2012. http://strokefoundation.com.au/health-professionals/clinical-guidelines/guidelines-for-the-assessment-and-management-of-absolute-cvd-risk/ (accessed Dec 2012).
7. MayoClinic.com. Daily aspirin therapy: understand the benefits and risks (updated 6 April 2012). http://www.mayoclinic.com/health/daily-aspirin-therapy/HB00073 (accessed Dec 2012).