These include enoxaparin, tinzaparin, dalteparin and certoparin. Evidence suggests they are as effective as unfractionated heparin in the treatment of thromboembolic events and are now being used for initial treatment. They have a longer duration of action than unfractionated heparin and do not need any monitoring. This means patients could be discharged from hospital earlier. Once the diagnosis has been confirmed, oral anticoagulation is initiated.
Heparin treatment is maintained until the activity of the oral coagulant is therapeutic.
This may take up to 5 days to allow any existing clotting factors to be cleared from the blood. Warfarin is usually used for oral anticoagulation. Other agents include nicoumalone and phenindione but these are seldom used. There are several ways of initiating warfarin. In many cases, though, subsequent measurement of the clotting status shows these doses to be excessive.