P2Y12 inhibitors (antiplatelets)
P2Y12 inhibitors block a receptor that platelets use to clump together, preventing them from forming clots. Clopidogrel is used after heart attacks, stent placement, and strokes, often together with aspirin. Bleeding is the main risk, and these drugs are usually stopped several days before surgery. Clopidogrel must be activated by the liver, so some genetic variants and interacting drugs such as omeprazole can weaken its effect.