Certified Registered Nurse Anesthetist (CRNA) Practice Exam

Which anticoagulant is most commonly administered orally and requires monitoring of INR levels?

1. Heparin

2. Clonidine

3. Coumadin

4. Mannitol

The correct answer is: Coumadin

The anticoagulant that is most commonly administered orally and requires monitoring of INR levels is Coumadin, which is the brand name for warfarin. Warfarin works by inhibiting the vitamin K-dependent clotting factors, which are important for normal blood coagulation. Because of its mechanism of action and the variability in how different patients metabolize the drug, monitoring is essential to ensure that the INR (International Normalized Ratio) stays within a therapeutic range. This is crucial because too high an INR may lead to increased risk of bleeding, while too low an INR may not provide sufficient anticoagulation to prevent thromboembolic events. The other medications listed do not fit the criteria for this question. Heparin is typically administered intravenously and is not given orally, nor does it require INR monitoring. Clonidine is not an anticoagulant; rather, it is an antihypertensive medication. Mannitol is an osmotic diuretic used primarily for conditions such as intracranial hypertension and is not related to anticoagulation. Therefore, the appropriateness of Coumadin as the correct answer highlights its significance in anticoagulation therapy and the necessity of INR monitoring in clinical practice.