Question

Which drugs needs continuous monitoring of prothrombin time ?

• A. Aspirin
• B. Lepirudin
• C. Digoxin
• D. Coumadin

Answer 1

The Correct Option is D

Step 1: Recognize the agent. Coumadin is the brand name for warfarin, a coumarin anticoagulant taken orally for thromboembolic prophylaxis and treatment.

Step 2: Connect mechanism to monitoring. By inhibiting the vitamin-K-dependent factors II, VII, IX and X, warfarin lengthens the prothrombin time. Clinicians track this PT as the INR and adjust the dose continuously to stay within the safe therapeutic window.

Step 3: Rule out the alternatives. Aspirin acts on platelets and needs no PT titration, lepirudin (a thrombin inhibitor) is followed by aPTT, and digoxin is guided by serum levels and ECG changes, not PT.

The vitamin-K-antagonist anticoagulant is the PT-monitored drug.\[\boxed{\text{Coumadin}}\]