Plavix, the trade name for the generic medication clopidogrel bisulfate, is an anti-platelet medication. Anti-platelet medications work to inhibit platelets from clumping together to form blood clots, thereby working as a blood thinner. Plavix, which has a lower rate of side effects than other similar medications, is the most prescribed anti-platelet medication (besides over-the-counter aspirin). Plavix, however, can induce side effects and has been associated with causing thrombotic thrombocytopenic purpura (TTP).
Indications
Plavix is prescribed to treat peripheral artery disease, which occurs when plaque (substance consisting of fat, cholesterol and calcium) builds up inside the arteries. The plaque narrows the arteries, increasing the risk of stroke. It is also prescribed to patients who have recently had a stroke, to help thin the blood to prevent another stroke. Plavix is used to prevent other events caused by blood clots including heart attack and angina (chest pain).
Plavix along with aspirin is often prescribed to prevent blood clots in patients who received an intracoronary stent, which is a tube inserted into the coronary artery to prevent constriction.
What is TTP?
Thrombotic thrombocytopenic purpura is the formation of blood clots in small blood vessels throughout the body. This long clinical name can be better understood if we break it down into each word. Thrombotic refers to the formation of the blood clots. Thrombocytopenic means that the platelet count in the blood is low. This is due to the fact that the platelets are all clumped together forming the clots. Purpura are purple bruises that occur on the skin. This is caused by the low platelet count in the blood, which leads to bleeding into the skin, excessive bleeding from cuts and even internal bleeding.
Early Signs
The earliest warning sign of the onset of TTP is the appearance of a skin rash. These purplish spots, caused by the bleeding under the skin, will appear on the skin and mucus membranes such as in and around the mouth. The presence of this early sign will prompt your doctor to perform a blood count to determine if the platelet level is low.
Symptoms
Plavix-induced TTP will have other associated symptoms including pale skin, weakness, fever, increased heart rate, shortness of breath and headache. TTP can also trigger speech changes, confusion, stroke, seizure or coma. Patients with TTP may also experience a decrease in the amount of urine or an increase in the amount of blood or protein present in the urine. TTP results in death in 10 to 20 percent of cases, according to research published in the February 2005 issue of the journal "Heart."
Theories/Speculation
The claim that the medication Plavix induces TTP is still an issue of study. It is estimated that only 4 patients out of 1 million exposed to Plavix develop TTP and the fact that Plavix is the cause is still debatable. In many cases the doctors cannot be sure that another medication or an underlying disease did not cause the TTP.
As discussed in the article in "Heart," doctors theorize that certain people have a genetic abnormality that induces an immune response that leads to Plavix actually causing an increased risk of platelet activation, which leads to TTP.
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