Hepatotoxicity associated with glucosamine and chondroitin sulfate in patients with chronic liver disease

Glucosamine and chondroitin sulfate are molecules involved in the formation of articular cartilage and are frequently used for symptom relief in patients with arthrosis. These molecules are well tolerated with scarce secondary effects. Very few cases of possible hepatotoxicity due to these substances have been described. The aim of this paper is to report the frequency of presumed glucosamine hepatotoxicity in patients with liver disease. A questionnaire was given to 151 consecutive patients with chronic liver disease of different etiology (mean age 59 years, 56.9% women) attended in an outpatient clinic with the aim of evaluating the frequency of consumption of these drugs and determine whether their use coincided with a worsening in liver function test results. Twenty-three patients (15.2%) recognized having taken products containing glucosamine or chondroitin sulfate previously or at the time of the questionnaire. Review of the clinical records and liver function tests identified 2 patients presenting an elevation in aminotransferase values temporarily associated with glucosamine treatment; one of the cases simultaneously presented a skin rash attributed to the drug. Review of these two patients and the cases described in the literature suggest toxicity of glucosamine and chondroitin sulfate. The clinical spectrum is variable, and the mechanism of toxicity is not clear but may involve reactions of hypersensitivity. The consumption of products containing glucosamine and/or chondroitin sulfate is frequent among patients with chronic liver diseases and should be taken into account on the appearance of alterations in liver function tests not explained by the underlying disease.