Clopidogrel is an antiplatelet drug used to reduce the risk of blood clotting in arteries and reduce the risk of heart attack and stroke. In case of an injury to a blood vessel wall, platelets get stimulated to produce chemicals, which in turn attract other platelets to stick together, forming a blood clot. Clopidogrel inhibits the platelet aggregation and formation of harmful blood clots. The brand name of clopidogrel is Plavix. There are other antiplatelet drugs, such as aspirin, prasugrel, and ticagrelor.
Dual antiplatelet therapy (DAP), i.e. combination of aspirin and clopidogrel (or aspirin and prasugrel or ticagrelor), are routinely used for 12 months following a heart attack or PCI to reduce the risk of another heart attack or stent thrombosis. It is essential not to prematurely discontinue this medication because particularly early after stent insertion, there very high risk of stent thrombosis with an ensuing large myocardial infarction. DAP can somewhat increase the risk of bleeding, and there are sometimes difficult decisions to be made if a patient on DAP needs an urgent surgical procedure. Still, in general, the benefits of DAP more than outweigh any potential risks.
Clopidogrel is usually well tolerated, but possible side effects include bleeding, indigestion, stomach pain, black stools, nausea or vomiting, rarely neutropenia (low white blood cell count). Omeprazole, the most commonly prescribed proton pump inhibitor (PPI), used to protect stomach lining in patients with a history of gastric or duodenal ulcers, reduces the efficacy of clopidogrel. A better option for patients on clopidogrel, who need a PPI, is lansoprazole with no interaction.