Which combination increases bleeding risk for patients taking anticoagulants such as Coumadin or warfarin?

Which combination increases bleeding risk for patients taking anticoagulants such as Coumadin or warfarin?

• A. Vitamin E
• B. Calcium & Magnesium
• C. Vitamin K
• D. Grapefruit

Answer: (B)

Warfarin’s bleeding risk rises when something increases its anticoagulant effect or raises the drug’s level in the blood. Vitamin K has the opposite effect of warfarin: it helps the body form clotting factors, so it reduces bleeding risk rather than increasing it. Vitamin E, especially in high doses, can interfere with platelet function and can enhance the anticoagulant effect of warfarin, leading to more bleeding. Grapefruit juice can inhibit liver enzymes that metabolize warfarin, potentially raising warfarin levels and bleeding risk, though the effect varies by person. Calcium and magnesium do not have a meaningful interaction with warfarin. So, substances that can increase bleeding risk among these options are vitamin E and grapefruit, not calcium and magnesium.

Warfarin’s bleeding risk rises when something increases its anticoagulant effect or raises the drug’s level in the blood. Vitamin K has the opposite effect of warfarin: it helps the body form clotting factors, so it reduces bleeding risk rather than increasing it. Vitamin E, especially in high doses, can interfere with platelet function and can enhance the anticoagulant effect of warfarin, leading to more bleeding. Grapefruit juice can inhibit liver enzymes that metabolize warfarin, potentially raising warfarin levels and bleeding risk, though the effect varies by person. Calcium and magnesium do not have a meaningful interaction with warfarin. So, substances that can increase bleeding risk among these options are vitamin E and grapefruit, not calcium and magnesium.