Low-Molecular Weight Heparin. Enoxaparin (Lovenox), dalteparin (Fragmin), tinzaparin (Innohep) are drugs known as low-molecular weight heparins (LMWHs). Many doctors now recommend these drugs over standard heparin for patients with unstable angina (unless bypass surgery is being planned). They have similar rates of survival, recurring angina, and bleeding as standard heparin. However, they pose lower risks for heart attack, repeat angioplasties, and thrombocytopenia. They require injections but do not require the ongoing monitoring that standard heparin does. Patients may even be able to self-administer LMWHs as people with diabetes do insulin.
Warfarin. Warfarin (Coumadin) is an oral anticoagulant. It prevents clots by inhibiting vitamin K. Warfarin is used with aspirin after a heart attack to prevent another one and to prevent blood clots in patients with atrial fibrillation. Warfarin is also proving to be more effective than aspirin for preventing heart attacks in patients with acute coronary syndromes. There is even some evidence that it might prevent disease progression itself in the arteries of the heart. Warfarin therapy must be monitored with frequent blood tests. In one study, bleeding occurred in 1% of patients taking aspirin or warfarin alone and in 2% taking a combination.
Direct Thrombin Inhibitors (DTIs). Direct thrombin inhibitors are a more recent group of anti-coagulants. The first DTI was hirudin, a natural substance derived from the saliva of leeches. New forms include argatroban (Novastan), bivalirudin (Angiomax), danaparoid (Orgaran), lepirudin (Refludan), desirudin (Revasc), and ximelagatran (Exanta). Many of these drugs are used along with warfarin and may be good options for patients who develop thrombocytopenia with heparin use. DTIs may prove to be superior to standard heparin for patients with acute coronary syndrome.
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