C-H Chang1, Y-W Wang, P-Y Yeh Liu, Y-H Kao Yang. 1. Institute of Clinical Pharmacy and Pharmaceutical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Abstract
WHAT IS KNOWN AND OBJECTIVE: The many interactions between warfarin and other drugs and foods generate great challenges for clinicians and patients in maintaining stable anitcoagulation. Interactions due to variable vitamin K content of different dietary items influence the therapy of nearly all patients on warfarin. Unfortunately, there is no widely acceptable, patient-friendly strategy for managing such interactions. In this contribution, we propose a practical approach to managing this troublesome interaction, consisting of 'maintaining constant weekly dietary vitamin K intake scores'. METHODS: Twenty-three vitamin K-rich vegetables commonly seen in Taiwanese meals were identified and classified into seven score grades according to their relative vitamin K content per serving. The scores were based on published vitamin K content of different foods. RESULTS AND DISCUSSION: The vitamin K score was equivalent to 5 points for spinach and garland chrysanthemum per bowel, followed by (baby) bok choy, amaranth, arden lettuce (4 points); leaf mustard, edible rape, sweet potato leaf, bai cai and Chinese leek (3 points); and okra and Chinese celery (0·5 points). This classification can be used to guide patients in recording their weekly vitamin K scores with a view to maintaining it when on warfarin. WHAT IS NEW AND CONCLUSION: We suggest a novel approach to patient counselling on warfarin to maintain consistent dietary vitamin K intake and achieve a more stable anticoagulation response. A prospective randomized controlled trial to validate this pragmatic approach would be useful.
WHAT IS KNOWN AND OBJECTIVE: The many interactions between warfarin and other drugs and foods generate great challenges for clinicians and patients in maintaining stable anitcoagulation. Interactions due to variable vitamin K content of different dietary items influence the therapy of nearly all patients on warfarin. Unfortunately, there is no widely acceptable, patient-friendly strategy for managing such interactions. In this contribution, we propose a practical approach to managing this troublesome interaction, consisting of 'maintaining constant weekly dietary vitamin K intake scores'. METHODS: Twenty-three vitamin K-rich vegetables commonly seen in Taiwanese meals were identified and classified into seven score grades according to their relative vitamin K content per serving. The scores were based on published vitamin K content of different foods. RESULTS AND DISCUSSION: The vitamin K score was equivalent to 5 points for spinach and garland chrysanthemum per bowel, followed by (baby) bok choy, amaranth, arden lettuce (4 points); leaf mustard, edible rape, sweet potato leaf, bai cai and Chineseleek (3 points); and okra and Chinese celery (0·5 points). This classification can be used to guide patients in recording their weekly vitamin K scores with a view to maintaining it when on warfarin. WHAT IS NEW AND CONCLUSION: We suggest a novel approach to patient counselling on warfarin to maintain consistent dietary vitamin K intake and achieve a more stable anticoagulation response. A prospective randomized controlled trial to validate this pragmatic approach would be useful.