Myocardial infarction after diet-induced warfarin resistance

Abstract

A 35-year-old woman was receiving warfarin sodium therapy for a prosthetic aortic valve. She sustained a myocardial infarction five weeks after beginning a diet of lettuce, broccoli, and turnip greens to lose weight. Excess dietary vitamin K can cause life-threatening consequences in patients on warfarin treatment.

Assessment of Healthcare Professionals’ Knowledge About Warfarin-Vitamin K Drug-Nutrient Interactions

“…For example, Kempin [25] reported a diet-induced warfarin resistance in two patients consuming large amounts of broccoli. Similarly, Walker [26] noted myocardial infarctions due to warfarin resistance in patients following weight loss diets, including large amounts of green leafy vegetables rich in vitamin K. In contrast, decreases in vitamin K intake are associated with warfarin potentiation and a tendency for abnormal bleeding. Colvin and Lloyd [29] documented severe coagulation defects attributed to dietary deficiencies of vitamin K1, and Chow [30] reported instability of anticoagulation with hemorrhagic complications in two warfarin-anticoagulated patients due to dietary modifications that lowered intake of vitamin K. Therefore, when the amount of vitamin K in the diet remains constant, regardless of the level of consumption, it poses little problem to anticoagulant dosing.…”

“…Since the influence of vitamin K on oral warfarin was demonstrated in humans [9,10], many reports have implicated Knowledge of Warfarin/Vitamin K Interactions dietary vitamin K as a factor contributing to unwanted disturbances in anticoagulation, sometimes with life-threatening consequences [25][26][27][28][29][30]. Increases in vitamin K intake can precipitate abnormal clotting or warfarin-resistance [25][26][27][28].…”

“…Increases in vitamin K intake can precipitate abnormal clotting or warfarin-resistance [25][26][27][28]. For example, Kempin [25] reported a diet-induced warfarin resistance in two patients consuming large amounts of broccoli.…”

Sprouting a warfarin interaction

“…5 A number of cases have been reported in the medical literature where abnormal coagulation has been precipitated by increased 6 -and decreased-dietary vitamin K intake. 7 Another causative dietary circumstance is a return to a usual diet after a hospital stay. 8 A number of foods have been recognised to be high in vitamin K-for example, liver and green vegetables, particularly of the Brassica family.…”

“…With a less severely raised INR, [5][6][7][8][9] warfarin should be stopped and 2.5 mg oral vitamin K should be administered if the patient is deemed to be at high risk of bleeding, 1 with possible repeat doses after 24 hours depending on response.…”