Dicumarol is a drug that impairs the utilization of vitamin K by the liver. Dicumarol therapy would decrease the plasma concentration of which of the following procoagulants
**Core Concept**
Dicumarol is an anticoagulant that functions by inhibiting the enzyme **vitamin K epoxide reductase**, which is necessary for the recycling of **vitamin K** in the liver. Vitamin K is essential for the gamma-carboxylation of certain clotting factors. The liver uses vitamin K to produce **clotting factors II, VII, IX, and X**, as well as **proteins C and S**.
**Why the Correct Answer is Right**
The correct answer would be a clotting factor that relies on vitamin K for its production. Since Dicumarol impairs vitamin K utilization, it would decrease the production of these clotting factors. **Clotting factors II, VII, IX, and X** are all dependent on vitamin K for their synthesis. Among these, the question likely seeks the one most directly and commonly associated with this process.
**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific option provided, we cannot directly address why it is incorrect, but any option not directly related to vitamin K-dependent clotting factors would be incorrect.
**Option B:** Similarly, without specifics, we assume any option not directly tied to the vitamin K-dependent clotting factors would be an incorrect choice.
**Option C:** This would be incorrect if it does not represent a vitamin K-dependent clotting factor.
**Option D:** This option is incorrect if it does not represent a clotting factor that is dependent on vitamin K for its synthesis.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that anticoagulants like Dicumarol, which interfere with vitamin K metabolism, will decrease the levels of vitamin K-dependent clotting factors, thereby exerting their anticoagulant effect. This is crucial in clinical management and monitoring of patients on such therapy.
**Correct Answer:** Correct Answer: D. Clotting factor II (prothrombin)