May reduce effectiveness of antidiabetic agents (eg, acarbose, acetohexamide, chlorpropamide, glipizide, glyburide, metformin, miglitol, pioglitazone, repaglinide, rosiglitazone, glimepiride, tolbutamide, troglitazone). Reduced effectiveness of doxorubicin, etoposide, teniposide. Elevated INR w/ & potentiation of anticoagulant effects of warfarin. Chitosan may form complexes w/ chondroitin sulfate decreasing its absorption.