Sunday, November 1, 2020

Coumadin loading dose

 Q: In an averaged frame patients, the initial recommended warfarin/coumarin dose is?

A) 5mg

B) 10 mg

Answer: A

The concept of "loading" dose of coumarin is no more acceptable unless a patient is known to require a higher dose of warfarin in the past. There are two rationales behind it. 

First, the "front-loading" of warfarin with 10 mg has shown to fail either rapid therapeutic anticoagulation or any therapeutic benefit, rather it can increase the risk of bleeding. 

Second, a higher loading dose (10 mg for the first few days) may cause a sudden fall in factors protein S and protein C, leading to a transient procoagulant state.



1. Crowther MA, Ginsberg JB, Kearon C, et al. A randomized trial comparing 5-mg and 10-mg warfarin loading doses. Arch Intern Med 1999; 159:46. 

2. Kovacs MJ, Rodger M, Anderson DR, et al. Comparison of 10-mg and 5-mg warfarin initiation nomograms together with low-molecular-weight heparin for outpatient treatment of acute venous thromboembolism. A randomized, double-blind, controlled trial. Ann Intern Med 2003; 138:714. 

3. Keeling D, Baglin T, Tait C, et al. Guidelines on oral anticoagulation with warfarin - fourth edition. Br J Haematol 2011; 154:311. 

4. Garcia P, Ruiz W, Loza Munárriz C. Warfarin initiation nomograms for venous thromboembolism. Cochrane Database Syst Rev 2016; :CD007699. 

5. Ansell J, Hirsh J, Hylek E, et al. Pharmacology and management of the vitamin K antagonists: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest 2008; 133:160S.

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