Erythromycin-induced decrease of intestinal absorption of vitamin K

Warfarin-induced thrombosis of the nasal mucosal microvasculature

Erythromycin-induced inhibition of warfarin metabolism

Erythrom ycin-induced inhibition of clotting factors synthesis

A 62-year-old woman complained to her physician of nose bleeds and red eyes. The woman had been receiving warfarin for 1 month because of deep venous thrombosis. Four days earlier, she had started treatment  with erythromycin for acute pharyngitis. Which of the following drug-induced changes was most likely responsible for the patient’s symptoms?