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Clot Busters - Other Medications Used with Clot Busters


Heart attack patients treated with clot busters are also given anticoagulants ( blood thinners) and antiplatelets (drugs that make the blood less sticky) to help prevent further clots from developing, and to help prevent clots that have developed from getting bigger.


Heparin is an anticoagulant that is given through an intravenous (IV) line in the arm during treatment with some clot busters (alteplase and reteplase). Because heparin affects the blood’s ability to clot, it can lead to bleeding problems. In early studies that combined clot busters and heparin, there were high rates of bleeding problems and stroke. Physicians now use lower doses of heparin to reduce this risk.

Low Molecular Weight Heparin

Finding the right dose of heparin for each patient is tricky; hospital staff must run blood tests and make dose adjustments if necessary. A newer type of heparin called low molecular weight heparin (LMWH) does not require such close monitoring. It is also easier to administer: LMWH is injected under the skin twice a day whereas regular heparin is given through an IV line in the arm. LMWH may be substituted for regular heparin in some heart attack patients treated with clot busters. One study showed that patients treated with LMWH and clot busters were less likely to die, suffer a heart attack or angina than those treated with regular heparin. However, there was no significant difference between the two treatments in women.21 There was also a tendency for people treated with LMWH to have more bleeding problems than those treated with regular heparin. This was especially true for patients older than 75 years.22

Aspirin & Antiplatelets

Antiplatelet medications make the blood less sticky, which helps prevent blood clots from forming. Aspirin is the most common antiplatelet. Studies show that the benefits of aspirin and clot busters appear to be additive. Combining the two medications reduces the chances of dying from a heart attack more than either aspirin or clot busters alone.23

Super Aspirins

Other antiplatelets include glycoprotein (GP) IIb/IIIa inhibitors. These medications are the so-called “super aspirins” because they work in a similar way to aspirin but have a much stronger effect. Abciximab (pronounced ab-six-i-mab) is one example of a super aspirin.

The combination of clot busters and super aspirins may be used in certain heart attack patients. Research studies suggest that while this combination is faster at restoring blood flow to the heart, this does not seem to lower the risk of dying after a heart attack.24 This combined therapy also seems to be riskier than clot busters alone. Patients treated with both drugs have a higher risk of bleeding complications and they are more likely to develop a dangerously low blood cell count than patients treated with clot busters alone. 25, 26 The increased bleeding risk seems to be confined to patients older than 75 years so combined therapy is usually avoided in older patients.

Direct Antithrombins

Direct antithrombins are a type of anticoagulant. They may be substituted for regular heparin in heart attack patients who experience an allergic reaction to heparin. Otherwise, direct thrombin inhibitors are not generally given to heart attack patients. Studies show that combining bivalirudin with clot busters reduces the risk of subsequent heart attack compared with regular heparin. However, this benefit is outweighed by a significant increase in bleeding problems.27


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