Doctors may prescribe a class of medications called anticoagulants, or blood thinners, to prevent blood clots from forming and to block the growth of existing clots. Depending on the type of anticoagulant prescribed, these medications may be taken by mouth, through a vein in the arm with intravenous (IV) infusion, or by subcutaneous injection, which delivers the mediation to a layer of fatty tissue under the skin.
For a sudden blood clot, warfarin and heparin are often prescribed in combination to people with antiphospholipid syndrome. Warfarin is taken by mouth, whereas heparin is given by injection or IV. Although heparin acts quickly to prevent the formation and growth of clots, warfarin may not be effective for two to three days. For this reason, your doctor typically recommends discontinuing the heparin only after the warfarin has taken effect.
Our doctors may also recommend that you take aspirin, which thins the blood by blocking the normal function of platelets, the blood cells responsible for forming blood clots. Sometimes aspirin is used in combination with warfarin, although it may be used alone.
Doctors usually treat pregnant women who have antiphospholipid syndrome with heparin, which includes a variation called low-molecular-weight heparin, or with a combination of heparin and low-dose aspirin. These medications are used to prevent recurrent pregnancy losses in women with a history of this complication of antiphospholipid syndrome. Warfarin cannot be used during pregnancy, because it may adversely affect the unborn child and lead to the loss of a pregnancy or a stillbirth.
The most common side effect of blood thinners is bleeding, which can happen if the medication thins the blood too much. This can be life threatening, especially if the bleeding is internal. Tell your doctor right away if you have any signs of serious bleeding, such as: unusual pain, swelling, or discomfort; prolonged bleeding due to cuts or gums; frequent nosebleeds; vomit that is bloody or looks like coffee grounds; or if you are coughing up blood.
Because anticoagulants are typically part of a long-term treatment plan, people receiving these blood thinners should have regular blood tests. This allows doctors to check how well their blood is clotting and whether they are taking the right amount of medication, so that clots are prevented but bleeding doesn’t occur.