Anticoagulation (Anticoagulants)
Anticoagulants are medications that are commonly called "blood thinners". The medication does not actually thin the blood, but rather prevent new blood clots from forming. Patients with venous thrombosis are usually treated first with an injectable anticoagulant called heparin. In some cases, unfractionated heparin is given into a vein while the patient is in the hospital. In other cases, heparin or another form of heparin, termed low molecular weight heparin, is injected under the skin.
Preparations of low molecular weight heparin include enoxaparin (Lovenox®), dalteparin (Fragmin®), or tinzaparin (Inohep®). These can be injected into the skin by the patient, a family member, or a home health nurse. This allows a person to be treated without requiring them to stay in the hospital. Heparin or low molecular weight heparin are usually continued for at least five days, along with another medication called warfarin (Coumadin®). Once the warfarin level has reached the desired target level (usually an International Normalized Ratio (INR) of 2 to 3), and this level is stable, the heparin is discontinued.
Warfarin (Coumadin®) is taken as a pill for a minimum of three months. Less commonly, the patient does not take warfarin but uses low molecular weight heparin for the entire treatment period. Low molecular weight heparin is much more expensive than warfarin, but does not need to be monitored with blood clotting tests (in people with normal kidney function), so this regimen may be used only in certain circumstances.
