**Core Concept**
Warfarin, a vitamin K antagonist, is used to treat and prevent thromboembolic events in patients with atrial fibrillation. The International Normalized Ratio (INR) is a measure of warfarin's anticoagulant effect. An INR of 6 indicates a high risk of bleeding and requires immediate action.

**Why the Correct Answer is Right**
An INR of 6 is above the therapeutic range (2-3) for most patients. This indicates excessive anticoagulation, increasing the risk of bleeding. The patient's INR needs to be corrected by administering fresh frozen plasma (FFP) or prothrombin complex concentrate (PCC) to reverse the anticoagulant effect of warfarin. The dose of warfarin should also be reduced or temporarily discontinued to prevent further accumulation of its active metabolites.

**Why Each Wrong Option is Incorrect**
* **Option A:** Administering more warfarin would further increase the INR, exacerbating the risk of bleeding. This option is incorrect because it would worsen the patient's condition.
* **Option B:** No action would allow the INR to remain elevated, increasing the risk of bleeding. This option is incorrect because it would neglect the patient's immediate need for anticoagulation reversal.
* **Option C:** Checking the patient's medication list for potential interactions is an important step, but it does not address the immediate need to correct the elevated INR. This option is incorrect because it is a necessary but not sufficient action.

**Clinical Pearl / High-Yield Fact**
When managing patients on warfarin, it is essential to regularly monitor their INR to prevent both thromboembolic events and bleeding complications. A target INR range should be set based on individual patient factors, such as the presence of atrial fibrillation or mechanical heart valves.

**Correct Answer:** C.