Which is an anticoagulant?

Coumadin, also known as warfarin, is classified as an anticoagulant because it functions by inhibiting the synthesis of vitamin K-dependent clotting factors in the liver. By interfering with the body's ability to form clots, it helps prevent thromboembolic events such as strokes and heart attacks. It is commonly prescribed for patients who are at risk of developing dangerous blood clots and requires careful monitoring of the patient’s INR (International Normalized Ratio) to ensure safe and effective dosing.

The other options represent different types of medications that serve different purposes. Ceclor is an antibiotic used to treat bacterial infections, Librium is a benzodiazepine used for anxiety and to manage alcohol withdrawal symptoms, and Prozac is an antidepressant in the selective serotonin reuptake inhibitor (SSRI) category used to treat depression and anxiety disorders. These drugs do not have the antithrombotic properties associated with anticoagulants, making Coumadin the choice that correctly fits the category of anticoagulants.