Q: Thyrotoxic patients with atrial fibrillation

A) require a lower maintenance dose of warfarin than euthyroid patients

or

B) require a higher maintenance dose of warfarin than euthyroid patients

(Select one)

Answer: A Thyrotoxic patients may require a lower maintenance dose of warfarin than euthyroid patients in atrial fibrillation because of increased clearance of vitamin K–dependent clotting factors.



Fadel BM, Ellahham S, Ringel MD, et al. Hyperthyroid heart disease. Clin Cardiol 2000;23: 402–8.