Can glucosamine and warfarin interact?/nThe question relates to a patient who is being treated with

Fråga: Can glucosamine and warfarin interact?

The question relates to a patient who is being treated with warfarin (dose unknown) and wants to try glucosamine for joint complaints.

Sammanfattning: There is no documentation on interactions between warfarin and glucosamine. Theoretically, no obvious drug interaction is expected but clinical data are lacking.

Svar: In a thorough literature search, including Medline, Embase, Drugline and other pharmacological sources no reports on drug interactions between warfarin and glucosamine have been found.

There is no obvious theoretical ground for a drug interaction although clinical data are lacking. The most active isomer of warfarin, S-warfarin, is extensively metabolised by cytochrome P450 CYP2C9 in the liver (1). Glucosamine is metabolised predominantly in the liver to smaller molecules and ultimately to carbon dioxide, water and urea (2). Glucosamine is an endogenous substrate for the biosynthesis of glucosamine glucanes, protoglucanes and hyaluronic acid, all components of joint tissue (3). Although glucosamine partly has a similar chemical structure of heparin (both containing glucosamine components) no untoward effect on blood clotting is expected since heparin only is active as a polymer (4).