an antiplatelet drug is a drug that acts against blood clotting. the blood contains platelets, which will stick together, and close an open wound. in some cases, they also stick together in the bloodstream, and form blood clots. such blood clots cause strokes and heart attacks. another type of drug that prevents clotting is called anticoagulant. anticoagulants cannot be used to prevent blood clotting in the arteries. antiplatelet drugs are commonly used in the prevention of strokes and heart attacks. acetylsalicylic acid, commonly known as aspirin, is one of them.