Blood Thinners - Page 6

Clopidogrel (Plavix) & Ticlopidine

What is clopidogrel?
Clopidogrel (Plavix) is an antiplatelet. Antiplatelets make the blood less sticky, which helps prevent blood clots from forming.

What is it used for?
Clopidogrel is given to people after a heart attack. Studies comparing clopidogrel with aspirin found that is was slightly better at reducing the risk of heart attack, stroke, or death, particularly in people who already had heart surgery and people with diabetes.^{30 31} Aspirin is such a well established and accepted treatment that clopidogrel is substituted for aspirin only in people who can't tolerate or are allergic to aspirin. Research now focuses on combining clopidogrel with aspirin.

Is it better to take clopidogrel and aspirin rather than aspirin alone?
One study found that after a mild heart attack, people took both aspirin and clopidogrel for up to 1 year were less likely to have a heart attack, stroke, or die compared with patients taking aspirin alone.³² If you have undergone angioplasty with or without stenting, you may also benefit from taking both antiplatelets for up to 1 year.³³ Although there was a strong suggestion that women benefited just as well as men, the results for women did not reach statistical significance. Combining clopidogrel and aspirin increases the risk of bleeding problems compared with aspirin alone.
A 2006 study suggests that the 2 drug combination should not be used in everyone at risk for heart disease. This trial involved more than 15,500 people 45 years of age or older from 32 countries including the US who had been diagnosed with cardiovascular disease or had multiple risk factors.³⁴ After more than 2 years, there was no difference in the risk of heart attack, stroke, or dying from heart disease between those who took clopidogrel and low-dose aspirin (75-162 mg) daily or low-dose aspirin plus a dummy pill. Indeed the 2 drug combination appeared to do more harm in the people who had risk factors.. It actually increased their risk of dying (5.4% versus. 3.8%) or dying specifically from cardiovascular disease (3.9% versus 2.2%). Most of these people had risk factors such as smoking, high blood pressure, and high cholesterol, but had not been diagnosed with cardiovascular disease. However, the multiple risk factor group also included some people who had had a heart attack, stroke, or heart procedure in the distant past (more than 5 years past).
When stents, the tiny wire mesh tubes that are inserted into blocked arteries during angioplasty to help prop the artery open, are implanted, there is a risk of damage to the artery that may trigger the formation of a life threatening blood clot. To prevent this, clopidogrel is prescribed for at least 1 month for a bare metal stent, and 3 to 6 months for drug-coated stents.⁷

What are the risks of clopidogrel?
Because clopidogrel interferes with blood clotting, it increases the risk of bleeding problems. One study found that people who had bypass surgery within 5 days of receiving clopidogrel were much more likely to have major bleeding problems than people who did not receive clopidogrel.³⁵ If you are undergoing bypass surgery, you should not take clopidogrel for 5 to 7 days before the procedure. Combining clopidogrel and aspirin increases the risk of bleeding problems compared with aspirin alone.

What is ticlopidine?
Ticlopidine (Ticlid) is another antiplatelet that is similar to clopidogrel. Ticlopidine has a number of serious side effects so it is rarely used as a first-line treatment. It causes side effects including diarrhea, nausea, and skin rash in as many as 20% of people who take it.³⁶ In rarer instances, ticlopidine may trigger a dangerously low white blood cell count ( neutropenia), which can be life threatening. Another potentially fatal complication is thrombotic thrombocytopenic purpura (TTP) – a dangerously low platelet count accompanied by a skin rash and clots in the small blood vessels.

Clopidogrel & Ticlopidine Quick Reference Table

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