Plavix, or clopidogrel, is an oral inhibitor of platelet aggregation, meaning it keeps platelets from sticking together. Plavix is indicated for reduction of clots in patients who have had a recent heart attack, stroke or who have peripheral arterial disease. It is also indicated in patients who are having a heart attack, or acute coronary syndrome, according to the "Physicians' Desk Reference," or the PDR.
Thrombotic Thrombocytopenic Purpura
Plavix has a warning on its label stating that rarely, after less than two weeks of treatment, a patient may develop thrombotic thrombocytopenic purpura, or TTP. According to "Harrison's Principles of Internal Medicine," TTP is often fatal and classically has five components, or a clinical pentad: low platelets, or thrombocytopenia; hemolytic anemia that causes red blood cells to fragment; neurological deficits that come and go, including confusion, delirium, and paralysis of one side of the body; renal dysfunction; and fever. The complete pentad is seen in approximately 30 percent of patients. A physician who sees fragmented red blood cells on a peripheral smear with thrombocytopenia has enough evidence to suspect TTP.
TTP is a medical emergency requiring hospitalization, plasma exchange or treatment with fresh frozen plasma.
Prolonged Bleeding
Plavix prolongs bleeding time due to an increase in the time it takes for the patient's blood to clot. It should be used cautiously in those at risk for increased bleeding from trauma or surgery or those patients with gastrointestinal or intraocular diseases, according to the PDR.
Recurrent Ulcer Bleeding
A clinical trial published in "The New England Journal of Medicine" looked at 320 patients who took aspirin to prevent heart attacks and stroke and who presented with ulcer bleeding. As stated by Dr. Francis K. L. Chan, after the ulcers healed, patients were randomly assigned: 161 to clopidogrel and 159 to aspirin plus esomeprazole, a heartburn medicine. Recurrent ulcer bleeding at 12 months occurred in 13 patients on clopidogrel (six with gastric ulcers, five with duodenal ulcers, two with both gastric and duodenal ulcers) and in one on aspirin plus esomeprazole (duodenal ulcer).
References
- "Harrison's Principles of Internal Medicine"; Dennis Kasper, M.D.; 2005
- "Physicians' Desk Reference, 63rd Edition"; 2009
- The New England Journal of Medicine: Clopidogrel versus Aspirin and Esomeprazole to Prevent Recurrent Ulcer Bleeding
