Clopidogrel is used to prevent strokes and heart attacks in persons who are at high risk. In one large study, clopidogrel was more effective than aspirin in reducing heart attacks. The frequency of side effects of clopidogrel was similar to aspirin; however, stomach and intestinal bleeding probably occurs less often with clopidogrel than with aspirin.
How to use
Take clopidogrel exactly as directed by your doctor. If you do not understand these instructions, ask your pharmacist, nurse, or doctor to explain them to you. Take each dose with a full glass of water. Clopidogrel can be taken with or without food.
Drug Class and Mechanism
Clopidogrel is an anti-platelet drug, that is, a drug that inhibits the ability of platelets to clump together as part of a blood clot. It is similar to ticlopidine (Ticlid) in chemical structure and in the way it works. Unlike ticlopidine, clopidogrel does not cause serious reductions of white cells in the blood and, therefore, routine blood testing to determine if the white blood cell count is low is not necessary during treatment. The risk of heart attacks and strokes (which usually are caused by blood clots) is increased in patients with a recent history of stroke or heart attack and patients with peripheral vascular disease. (Peripheral vascular disease is the same as atherosclerotic arterial disease or "hardening" of the arteries in which the arteries become narrowed. It frequently occurs in the legs and often causes claudication or pain in the legs upon walking). Clopidogrel is used to reduce the risk of heart attacks and strokes in these patients. Clopidogrel was approved by the FDA in 1997.
Take the missed dose as soon as you remember. However, if it is almost time for the next dose, skip the missed dose and take only the next regularly scheduled dose. Do not take a double dose of this medication.
Tablets should be stored at room temperature, 15-30 degrees C (59-86 degrees F), away from moisture and heat.
Possible Side Effects
The tolerability of clopidogrel is similar to that of aspirin. Diarrhea, rash, or itching occurs in approximately 1 in 20 persons taking clopidogrel. Abdominal pain also occurs in about 1 in 20 persons, but it is less frequent than with aspirin.
Ticlopidine (Ticlid) is an antiplatelet medication quite similar to clopidogrel. It has been associated with a severe reduction in white blood cell count in between 0.8% and 1% of persons. The risk of this dangerous side effect with clopidogrel is about 0.04%, much less than with ticlopidine but twice that of aspirin.
Clopidogrel rarely causes a condition called thrombotic thrombocytopenic purpura (TTP) in one out of every 250,000 people. TTP is a serious condition in which blood clots form throughout the body. Blood platelets, which participate in clotting, are consumed, and the result can be bleeding because enough platelets are no longer left to allow blood to clot normally. For comparison, the related drug, ticlodipine (Ticlid), causes TTP 17-50 times more frequently than clopidogrel.
If you experience any of the following serious side effects, stop taking clopidogrel and seek emergency medical attention or notify your doctor immediately:
an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives);
bloody (or black) vomit or stools;
severe headache, confusion, or dizziness;
unexplained bruising or bleeding; or
Other, less serious side effects may be more likely to occur. Continue to take clopidogrel and talk to your doctor if you experience
diarrhea or constipation; or
headache or dizziness.
Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.