Examples
Coumarins
| Brand Name | Generic Name |
|---|---|
Low-molecular-weight heparins (LMWH)
| Brand Name | Generic Name |
|---|---|
Antithrombotic medications
| Brand Name | Generic Name |
|---|---|
Unfractionated heparins (UH)
| Generic Name |
|---|
How It Works
Anticoagulant medications (also known as blood thinners) help prevent the formation of blood clots by increasing the time it takes a blood clot to form. This prevents a clot that has already formed from getting larger and reduces the chances that pieces of a clot will break off and cause a heart attack or stroke.
Why It Is Used
Anticoagulants are used in the treatment of mitral valve regurgitation and aortic valve regurgitation:
- When atrial fibrillation is present.
- After valve surgery. At this time there is an increased risk for blood clots. If you have a mechanical valve (made with metal or plastic), you will have to take anticoagulants for the rest of your life.
After heart valve replacement surgery, both Coumadin (warfarin) and one of several types of anticoagulant medications—a low-molecular-weight heparin, an unfractionated heparin, or an antithrombotic medication—are started. Coumadin is given in pill form while the other medications are given as a shot. The injected medications (low-molecular-weight heparin, unfractionated heparin, and antithrombotic medications) act immediately, while Coumadin takes several days to become effective. Once Coumadin begins to work, the other medications are stopped.
How Well It Works
Anticoagulants prevent clotting of a mechanical heart valve. Anticoagulants have also been shown to reduce the risk of stroke in people who have atrial fibrillation.1
Side Effects
Anticoagulants may cause:
- Easy bruising.
- Bleeding in the brain.
- Bleeding in the stomach and intestines.
- Skin rash.
See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)
What To Think About
If you are taking anticoagulants, notify your doctor immediately if you:
- Have unusual bruising or red or purple spots on the skin.
- Have unusual bleeding from the nose or gums, or if you are spitting up blood.
- Have blood in your urine.
- Have red or black (tarry) stools.
- Have been vomiting blood or material that looks like coffee grounds.
- Have abnormally long menstrual periods.
Safety tips when taking anticoagulants may be helpful, such as taking your medications at the same time each day and watching for signs of bleeding.
What to do if you miss a dose of anticoagulant:
- If you remember it in the same day, take the missed dose. Then go back to your regular schedule.
- If it is the next day, or almost time to take the next dose, do not take the missed dose. Do not double the dose to make up for the missed one. At your next regularly scheduled time, take your normal anticoagulant dose.
- If you miss your dose for 2 or more days, call your doctor.
Do not double the dose in any one day to make up for a missed dose. Call your doctor if you are not sure what to do if you missed a dose.
You will need to have your blood drawn frequently while taking some anticoagulant medications. Anticoagulant therapy requires regular monitoring because high levels of anticoagulants increase the risk of bleeding, while levels that are too low increase the risk of stroke and heart attack.
Women have a higher incidence of bleeding while taking anticoagulants than do men and require more frequent monitoring.2
Some anticoagulants pose a definite risk to a fetus. Pregnant women are generally not advised to take Coumadin (warfarin), because it is known to cause birth defects. If you become pregnant while taking Coumadin, your doctor may recommend that you switch to a low-molecular-weight form of heparin (another anticoagulant) during the first and third trimesters of your pregnancy, and take Coumadin only during the second trimester. Long-term use of these heparin formulations is not recommended, because it is associated with osteoporosis and thrombocytopenia.
Always talk to your health professional before using any anticoagulant during pregnancy or if you become pregnant while using them. Check with your doctor immediately if you are taking an anticoagulant and think you may be pregnant.
Anticoagulants interact with other medications and foods. Talk to your doctor or pharmacist about possible interactions anticoagulants may have with your current medications.
Special care should be taken when you shave and when brushing and flossing your teeth:
- Use only a soft toothbrush and floss very gently.
- Use an electric razor instead of a blade.
Do not drink alcohol while taking anticoagulant medications. Alcohol can change the way an anticoagulant works.
Do not participate in contact sports or other potentially hazardous activities while taking anticoagulant medications. Report any falls, blows to the body or head, or other injuries to your doctor immediately.
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References
Citations
Lip GYH, et al. (2006). Stroke prevention, search date September 2005. Online version of BMJ Clinical Evidence. Also available online: http://www.clinicalevidence.com.
Humphries KH, et al. (2001). New-onset atrial fibrillation: Sex differences in presentation, treatment, and outcome. Circulation, 103(19): 2365–2370.
| Author: | Robin Parks, MS | Last Updated: January 24, 2008 |
| Medical Review: | E. Gregory Thompson, MD - Internal Medicine Stephen Fort, MD, MRCP, FRCPC - Interventional Cardiology | |

