What is a potential interaction associated with glucosamine?

• A. Can increase warfarin effect
• B. Reduces warfarin effect
• C. No interaction
• D. Interacts with beta-blockers

Answer: (A)

Glucosamine can boost the effect of warfarin, increasing the risk of bleeding. Warfarin inhibits vitamin K–dependent clotting factors, so anything that raises its activity or levels can tip the balance toward excessive anticoagulation. There are case reports of higher INR when people start glucosamine while on warfarin, and while the exact mechanism isn’t fully clear, it’s a recognized potential interaction. Practically, if a patient is taking warfarin and glucosamine is added, INR should be monitored more closely and warfarin dose adjusted if needed or the combination reconsidered. The idea that there’s no interaction isn’t supported by these reports, and interactions with beta-blockers aren’t a typical concern with glucosamine.