Warfarin
Does it work?
No. Adding warfarin to the usual treatment for unstable angina doesn't help. And it can increase your risk of bleeding. So this medicine isn't commonly used to treat unstable angina.
What is it?
Warfarin (brand name Marevan) is a drug that helps stop your blood clotting. It can't break up clots, but it can stop them getting bigger.
How can it help?
It doesn't.[1] [2] [3] [4] Taking warfarin as well as the usual treatments for unstable angina doesn't affect whether you will get angina again or have a heart attack. And it doesn't affect whether you will die as a result of your unstable angina.
Why should it work?
If you get unstable angina, your heart isn't getting enough oxygen. This happens because one or more of the arteries that supply blood to your heart (your coronary arteries) are partly blocked by blood clots.
Warfarin stops clots getting bigger and stops new clots forming. So doctors had hoped it would lower people's risk of getting more angina attacks and complications, such as heart attacks. But it doesn't.
Can it be harmful?
Yes. Drugs that stop clots forming, such as warfarin and heparin, can cause bleeding. But doctors feel that the small chance of bleeding is a risk worth taking if the medicine works.
However, warfarin does not lower the risk of heart attacks for people with unstable angina or save their lives. That means the risk is not worthwhile.
Here is what one study showed.[3]
- About 27 in 1,000 people who took warfarin as well as the usual treatments for unstable angina got serious bleeding.
- But only about half that many, 13 in 1,000 people, who took only the usual treatments got serious bleeding.
References
- Cohen M, Adams PC, Parry G, et al. Combination antithrombotic therapy in unstable rest angina and non-Q-wave infarction in nonprior aspirin users: primary end points analysis from the ATACS trial. Circulation. 1994; 89: 81-88.
- Anand SS, Yusuf S, Pogue J, et al. Long-term oral anticoagulant therapy in patients with unstable angina or suspected non-Q-wave myocardial infarction: organization to assess strategies for ischaemic syndromes (OASIS) pilot study results. Circulation. 1998; 98: 1064-1070.
- OASIS Investigators. Effects of long-term, moderate-intensity oral anticoagulation in addition to aspirin in unstable angina. Journal of the American College of Cardiology. 2001; 37: 475-484.
- Hunyh T, Theroux P, Bogaty P, et al. Aspirin, warfarin, or the combination for secondary prevention of coronary events in patients with acute coronary syndromes and prior coronary artery bypass surgery. Circulation. 2001; 103: 3069-3074.
Glossary
- heart attack
- Doctors call a heart attack an acute myocardial infarction (or acute MI). This is the name for the damage that occurs to the heart muscle if it isn't getting enough blood and oxygen because a branch of the is blocked. During a heart attack, you may have pain or heaviness over your chest, and pain, numbness or tingling in your jaw and left arm.
- coronary arteries
- Coronary arteries are the vessels that supply blood to the heart muscle. If yours are blocked, you may have a pain in your chest (known as ) or a heart attack (what doctors call an ) because parts of the heart are not getting enough blood and oxygen.
© BMJ Publishing Group Limited ("BMJ Group") 2007. All rights reserved
This information does not replace medical advice. If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.
