All about warfarin are true EXCEPT?
**Core Concept**
Warfarin is an oral **anticoagulant** that functions as a **vitamin K antagonist**, inhibiting the synthesis of **vitamin K-dependent clotting factors** in the liver. This mechanism is crucial for its therapeutic and adverse effects. The drug's onset of action is delayed, requiring several days for peak anticoagulant effect.
**Why the Correct Answer is Right**
Given the options are missing, let's focus on warfarin's general properties. Warfarin inhibits **gamma-glutamyl carboxylase**, an enzyme necessary for the activation of **clotting factors II, VII, IX, and X**, as well as **proteins C and S**, which are involved in the regulation of coagulation. This inhibition leads to a decrease in the production of these factors, resulting in an anticoagulant effect.
**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific option text, we can't directly address why it's incorrect, but typically, incorrect statements about warfarin might involve its mechanism, duration of action, or interactions.
**Option B:** Similarly, without the text, we can't provide a detailed explanation, but incorrect options might include statements about warfarin's indications, contraindications, or monitoring parameters.
**Option C:**
**Option D:**
**Clinical Pearl / High-Yield Fact**
A crucial point to remember about warfarin is the importance of monitoring **INR (International Normalized Ratio)** to adjust dosages and prevent both thrombotic and bleeding complications. The therapeutic range for INR varies depending on the indication for anticoagulation.
**Correct Answer:**